Motor Noise Research Articles

Analytical model of electromagnetic torque of surface PM motors considering current harmonicsin electric vehicles

The modeling of the magnetic field, as well as the amplitude prediction and source analysis of torque ripple, are the theoretical basis to reduce the vibration and noise of electric motors. An analytical model of electromagnetic torque of surface permanent magnet motors considering current harmonics, which is capable of purely analytical calculation and theoretical analysis, is proposed in this paper. The open-circuit magnetic field solution considering the stator slot is performed by using the analytical conformal mapping along the deformed solving path, allowing more accurate prediction of the cogging torque. The armature reaction field is derived under any current condition with current harmonics. So far, the analytical model of electromagnetic torque is established, and the purely analytical calculation of torque value and the theoretical analysis of torque ripple characteristics are implemented in an 8-pole-24-slot surface permanent magnet motor used for the propulsion of light electric vehicles. The generation mechanism of constant torque and torque ripple is clarified both under sinusoidal current and harmonic current. Furthermore, the effect of the stator skew slot on the motor torque is well explained to demonstrate the utility of the proposed model. It is found that the skew slot is almost ineffective in mitigating the torque ripple caused by current harmonics.

Experimental investigation of mechanical, acoustic and hybrid metamaterial designs for enhanced and multi-band electric motor noise dissipation

Acoustic metastructures exhibit an unprecedented ability to arbitrarily manipulate the properties of sound waves, including amplitude and phase modulation which has attracted much attention in both the academic and industrial communities. Design of metastructures has been extensively investigated for the purpose of the independent manipulation of acoustic and elastic waves. It is up to now unclear however if the optimal dissipation approach involves locally resonant structural elements, or locally resonant acoustic cavities or a hybrid mix of both noise abatement mechanisms. To study this problem, we investigate numerically and experimentally the noise reduction performance of acoustic and mechanically locally resonant structures and how they perform when integrated into the same application scenario. Taking the noise emission of an electric motor as the excitation regime for our study, the acoustic and mechanical metamaterial structures with respective C-shape and T-shaped resonators are judiciously designed to maximize noise dissipation within two targeted frequency bands where the motor noise peaks. A hybrid structure with a mix of both resonators is also designed. The results demonstrate that all three metastructure designs improved the noise attenuation performance with an additional sound insertion loss of up to 16 dB when compared to a flat wall structure of equivalent mass. The findings in this work demonstrate that significant noise attenuation can be obtained by incorporating these acoustic and mechanical meta-atoms into a wall architecture which may have great potential for real world applications such as surrounding electric motors which tend to emit monotonic and irritating noise.

Application of Deep Learning in Motor Vibration and Noise Suppression Based on Negative Magnetostrictive Effect

Application of Deep Learning in Motor Vibration and Noise Suppression Based on Negative Magnetostrictive Effect

Simulation Analysis on Electromagnetic Vibration and Noise of Novel Mechatronic-Electro-Hydraulic Coupler

The mechatronic-electro-hydraulic coupler (MEHC) is a novel type of multisource coupling power device which integrates a traditional permanent magnet synchronous motor with a swash plate axial piston pump/motor to realize the mutual conversion of electrical energy, mechanical energy, and hydraulic energy. In order to improve the MEHC’s noise, vibration, and harshness performance, an electromagnetic vibration and noise simulation analysis was performed with a six-pole 36-slot motor as the research object. Firstly, the spatial order and frequency of the radial electromagnetic force were deduced by an analytical method. Subsequently, the electromagnetic field was simulated, and the electromagnetic force was extracted via a fast Fourier transform using Ansys/Maxwell software for the numerical verification. Thereafter, the harmonic response module coupled the electromagnetic field with the structural field for the harmonic response analysis. Ultimately, the research results were imported into the harmonic acoustics module for a noise simulation analysis and two different-shape magnetic isolation bridges optimization schemes were proposed. The results suggested that both optimisation solutions could effectively reduce motor vibration and noise. Scheme one reduced the maximum noise by about 6.5% and scheme two by 10.4%. The analysis process and conclusion provide a theoretical basis for the vibration and noise analysis of permanent magnet synchronous motors with different integer slots.

Lightweight soundproofing meta-panel for separate wide frequency bands

We propose a lightweight soundproofing meta-panel that suppresses noise in separate wide frequency bands. The meta-panel has a multi-scale lattice structure sandwiched by two thin membranes. High sound isolation over a wide frequency range is achieved by inducing negative effective material properties of the meta-panel. Unlike a single-scale lattice structure, in which total transmission is unavoidable at certain frequencies due to resonances of the membranes, the meta-panel isolates sound waves effectively in separate wide bands with the aid of multiple reflections within the multi-scale lattice structure. A sound transmission loss exceeding 16.7 dB was realized within the range 100–1750 Hz by a meta-panel sample fabricated via three-dimensional printing. Aiming at practical applications in electric cars, we evaluated the insertion loss of the meta-panel in a box-shaped structure for dual-band noise which consists of road noise (100–400 Hz) and motor noise (1050–1350 Hz) recorded from an actual electric car. The proposed meta-panel had an overall sound pressure level reduction of about 19 dB for the given dual-band noise with a small areal density of 1.51 kg/m2, which is 1/20 times lighter than a steel plate with an equivalent reduction level.

The Feature Recognition of Motor Noise Based on the Improved EEMD Model.

The noise generated by the machine is closely related to the running state of the machine, so the product can be effectively detected by analyzing the noise signal. The noise identification and control methods based on the EEMD model are widely used in motor noise control. However, the EEMD only considers the influence of noise amplitude on the decomposition results, and the added white noise cannot be completely neutralized. In this paper, an improved EEMD method is proposed by analyzing the influence of the maximum frequency on the decomposition results, in which the noise with different maximum frequency and amplitude is added to decompose the signal, and the decomposition effect is judged by the orthogonality coefficient of the decomposition result. Finally, the simulation signal and the measured signal are compared and analyzed, and the results show that the improved EEMD method has some advantages over the original method in suppressing mode confusion and fault diagnosis.

Motor noise reduction of unmanned aerial vehicles

The noise of multi-rotor unmanned aerial vehicles (UAVs) mainly comes from high-speed rotating propellers and brushless direct current motors. With extensive research on the generation mechanism and suppression methods of propeller noise, fruitful results have been achieved on the noise reduction of propellers. Therefore, the noise radiated by UAV motors has received more attention in recent years. In this paper, the noise of the motor of a small quadrotor UAV is reduced by a composite sound-absorbing structure that couples a cylindrical micro-perforated panel absorber (MPPA) with a carbon fiber porous material. The cylindrical MPPA adopts an open design to balance its noise reduction performance and heat dissipation performance. To more realistically reproduce the actual working state of the motor, different shapes of motor loads were designed and manufactured to simulate the propeller. The noise reduction experiment of the UAV motor is carried out in a semi-anechoic chamber. The experimental results show that the composite sound-absorbing structure designed in this paper can effectively reduce the noise of UAV motors and has a good heat dissipation effect. In addition, a custom-made composite sound-absorbing structure was installed on a quad-rotor UAV, and field experiments were carried out. The results of field experiments show that the composite sound-absorbing structure designed in this paper has good practicability to absorb the noise of UAV motors, and this work can provide a reference for the design of silent UAVs in the future.

Simulation, Verification and Optimization Design of Electromagnetic Vibration and Noise of Permanent Magnet Synchronous Motor for Vehicle

Aiming at the electromagnetic vibration and noise problem of an 8-pole 48-slot permanent magnet synchronous motor for a vehicle, the multi-physics coupling simulation model of the motor is introduced to optimize the rotor structure of the motor to reduce the vibration and noise of the permanent magnet synchronous motor. The effectiveness of the research method is verified by the bench test in the anechoic chamber. Finite element software was used to establish the stator core and system model considering the anisotropy of materials, and the simulation model was verified by modal experiment. For the 2in1 electric drive system, the electromagnetic-structure-acoustic multi-physics coupling noise prediction model is established. Based on the three-dimensional distributed electromagnetic force excitation, the electromagnetic radiation noise of the motor under full load acceleration is calculated, and the characteristics of electromagnetic noise are analyzed. The accuracy of the electromagnetic-structure-acoustic multi-physics coupling model of permanent magnet synchronous motor is verified by the bench test results of the anechoic chamber. By changing the angle and shape of the motor rotor, the cogging torque ripple between the stator and the rotor is reduced, and the 48th order harmonic amplitude is reduced. Finally, the optimized sample is tested on the vehicle, and the 48th order electromagnetic noise can be reduced by 5–15 dB(A). The accuracy of the electromagnetic-structure-acoustic multi-physics coupling model of permanent magnet synchronous motor is verified by the bench test results of the anechoic chamber. Therefore, the research results can be further used for the design and development of a vehicle permanent magnet synchronous motor and the research on the mechanism of electromagnetic vibration and noise.

Effect of vibrotactile stimulation of the hallux nail on segmental coordination: A secondary analysis using uncontrolled manifold analysis

Controlling center of mass (CoM) movement in the mediolateral direction is imperative for stable walking. During walking, CoM movement is adjusted by the coordination of each body segment, which can be evaluated using uncontrolled manifold (UCM) analysis. UCM analysis evaluates segmental coordination by analyzing variablity in motor movement among the different segments of the body. The vibrotactile stimulation of the hallux nail can augment the sensory information of the plantar surface for necessary motor control. This study aims to investigate the effect of the vibrotactile stimulation of the hallux nail on segmental coordination to control CoM movement in the mediolateral direction during walking. Thirteen healthy men participated in the study. A vibrator was attached to each hallux nail, and pressure sensors were placed under the hallux balls. When the hallux ball was in contact with the floor, vibration stimulation was applied. A three-dimensional motion analysis system was used to measure the segment angles during walking, and UCM analysis was used to evaluate kinematic synergy for controlling CoM movement in the mediolateral direction. Subsequently, segment angles were used as an elemental variable. The synergy index and bad variability as motor noise were negatively related to the status without the stimulation. Vibrotactile stimulation in young people was more effective for people with large motor noise and a small synergy index during the single-stance phase. Thus, kinematic synergy can be immediately changed by sensory input using vibrotactile stimulation of the hallux nail, although applying vibration stimulation should be considered in advance.

Low Gain Values of the Vestibulo-Ocular Reflex Can Optimize Retinal Image Slip.

The angular vestibulo-ocular reflex (aVOR) stabilizes retinal images by counter-rotating the eyes during head rotations. Perfect compensatory movements would thus rotate the eyes exactly opposite to the head, that is, eyes vs. head would exhibit a unity gain. However, in many species, but also in elderly humans or patients with a history of vestibular damage, the aVOR is far from compensatory with gains that are in part considerably lower than unity. The reason for this apparent suboptimality is unknown. Here, we propose that low VOR gain values reflect an optimal adaptation to sensory and motor signal variability. According to this hypothesis, gaze stabilization mechanisms that aim at minimizing the overall retinal image slip must consider the effects of (1) sensory and motor noise and (2) dynamic constraints of peripheral and central nervous processing. We demonstrate that a computational model for optimizing retinal image slip in the presence of such constraints of signal processing in fact predicts gain values smaller than unity. We further show specifically for tadpoles of the clawed toad, Xenopus laevis with particularly low gain values that previously reported VOR gains quantitatively correspond to the observed variability of eye movements and thus constitute an optimal adaptation mechanism. We thus hypothesize that lower VOR gain values in elderly human subjects or recovered patients with a history of vestibular damage may be the sign of an optimization given higher noise levels rather than a direct consequence of the damage, such as an inability of executing fast compensatory eye movements.

Analysis of electromagnetic vibration and noise of permanent magnet synchronous motor based on field-circuit coupling

In order to study the influence of harmonics on the vibration and noise of permanent magnet synchronous motor, this paper introduces an analysis method based on field-circuit coupling, and establishes a complete analysis process from the control strategy to the vibration and noise response of the motor. Firstly, the coupling model including control strategy, main circuit model and electromagnetic field model is established. Secondly, the finite element model of the permanent magnet synchronous motor under the influence of coupling is established to analyze and compare the electromagnetic force wave characteristics of the coupling excitation and the sinusoidal excitation. Then, the coupled electromagnetic force is loaded into the structural field to simulate and calculate the vibration and noise. Finally, the effectiveness of the model is verified through experimental sound pressure level comparison under steady-state and speed-up conditions, and it provides a reference for vibration and noise prediction of the motor system.

Influence of excitation current on electromagnetic vibration and noise of rotor magnetic shunt hybrid excitation synchronous motor

To explore the influence of the excitation current in the rotor magnetic shunt hybrid excitation synchronous motor (HESM) on the vibration and noise of the motor, the finite element analysis of the hybrid excitation motor was carried out by using ANSYS Workbench software and noise sources for analysis. Firstly, air-gap flux density at different excitation currents and density vector diagrams are studied. Secondly, radial electromagnetic force’s order and frequency characteristics under different excitation currents are discussed. Finally, the modal analysis of the stator of the motor is carried out. The motor’s vibration response and noise variation under different excitation current conditions are summarized. The simulation analysis and experimental verify that the motor’s vibration response and noise increase obviously when the excitation current is significant, and the vibration acceleration of different orders increases.

Coupling Analysis of Electromagnetic Vibration and Noise of FeCo-Based Permanent-Magnet Synchronous Motor

Addressing the problem of the vibration and noise of a permanent-magnet synchronous motor (PMSM), this paper optimizes the structure of a permanent-magnet motor rotator, introduces the electromagnetic-structure-acoustic coupling calculation model, and optimizes the motor rotator to reduce the vibration and noise of a permanent-magnet motor. Using the theory of Maxwell’s stress equation, the radial electromagnetic force on the stator teeth of the permanent-magnet motor is deduced and analyzed, and the correctness of the analysis calculation is verified by using the finite element multi-physical field coupling method. Based on the deduced analytical expression of the radial electromagnetic force, the sources of the radial electromagnetic force for each order and the frequency of the permanent-magnet motor are summarized. A 12-slot, 8-pole, permanent-magnet motor is taken as an example. A calculation model considering the spatial distribution of the radial electromagnetic force and the electromagnetic vibration of an iron-cobalt-based stator is established. The harmonic response of the electromagnetic vibration of the motor is analyzed, and a modal analysis is carried out. The optimized acceleration vibration noise cascade of the FeCo-based permanent-magnet drive motor under load is given. The correctness and validity of the theoretical derivation and simulation are verified by experiments.

Analysis and Mitigation of the Common-Mode Noise in a Three-Phase SiC-Based Brushless DC Motor Drive With 120° Conduction Mode

The generation and propagation of the common-mode (CM) noise depends on the pulsewidth modulation (PWM) technique, parasitic capacitances, and rate of change of voltages imposed on the motor. In the literature, the CM noise analysis of the brushless dc (BLdc) drive operated with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$120^\circ$</tex-math></inline-formula> conduction mode is reported neglecting the impact of the floating phase, and the analysis is restricted to low-voltage silicon-based drives. In this article, an in-depth theoretical analysis of the CM noise in the BLdc drive is presented considering two commonly used schemes in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$120^\circ$</tex-math></inline-formula> conduction mode: six-step commutation and bipolar PWM. It is proven through experiments that the impact of the floating phase cannot be neglected especially with the high-voltage slew rate imposed by silicon carbide (SiC)-based inverters on the drives. By considering the impact of the floating phase, the CM noise in the BLdc drive is modeled through mathematical equations, and suitable equivalent circuits are presented. Finally, a step-by-step design procedure of the CM filter for the BLdc drive is presented. Experimental results on a three-phase star-connected SiC-based BLdc drive are provided to substantiate the analysis and CM filter design.

Analysis on characteristic of 3.3‐kV full SiC device and railway traction converter design

With the rapid development of wide-band gap semiconductor chip and package technologies, the voltage class of commercial silicon carbide (SiC) device is gradually improved. This paper concentrates on the latest 3.3-kV full SiC-based metal oxide semiconductor field-effect transistor (MOSFET) device and its application in railway traction. First, compared with the Si-based insulated-gate bipolar transistor (IGBT), the SiC-based MOSFET shows lower switching loss but weaker short-circuit capacity. Second, in the railway traction application, the SiC-based MOSFET with high switching frequency could reduce the inverter loss, the harmonic loss and the noise of traction motor. Third, a well-designed filter is necessary between the inverter and the motor to prevent the motor from terminal overvoltage and insulation problem, which are resulted from long cable and high dv/dt. Finally, a full-SiC railway traction inverter prototype is built and tested, and shows obvious advantages on miniaturization and lightweight.

Motor Coordination and Strategic Cooperation in Joint Action

Naturalistic joint action between two agents typically requires both motor coordination and strategic cooperation. However, these two fundamental processes have systematically been studied independently. We presented 50 dyads of adult participants with a novel collaborative task that combined different levels of motor noise with different levels of strategic noise, to determine whether the sense of agency (the experience of control over an action) reflects the interplay between these low-level (motor) and high-level (strategic) dimensions. We also examined how dominance in motor control could influence prosocial behaviors. We found that self-agency was particularly dependent on motor cues, whereas joint agency was particularly dependent on strategic cues. We suggest that the prime importance of strategic cues to joint agency reflects the co-representation of coagents’ interests during the task. Furthermore, we observed a reduction in prosocial strategies in agents who exerted dominant motor control over joint action, showing that the strategic dimension of human interactions is also susceptible to the influence of low-level motor characteristics.

Rapid Calculation and Optimization of Vibration and Noise of Permanent-Magnet Synchronous Motors for EVs Based on Equivalent Structural Network

Optimizing electromagnetic performance and vibration noise performance simultaneously is important when designing the drive motor for electric vehicles (EVs). This has not been fully explored, and there are only a few relevant studies. To achieve simultaneous optimization, this paper proposes an equivalent structural network (ESN) of stator assembly to calculate the modal distribution and harmonic response transfer functions. Based on the ESN model, the motor’s electromagnetic vibration noise harmonic response, such as acceleration and equivalent radiated power level (ERPL), can be quickly calculated. The feasibility of the established ESN model is verified by structural-field finite-element method (FEM) and modal hammer tests. Based on the modern optimization algorithm and the ESN model, an improved multi-physics and multi-objective optimization design approach is proposed for an optimized design of a 30 kW interior permanent-magnet synchronous machine (IPMSM). The motor’s maximum output torque and ERPL were selected as optimization objectives, and then the ERPL and acceleration were recalculated using structural-field FEM to validate the accuracy of the optimal design. Finally, vibration acceleration tests were carried out on a manufactured prototype motor to verify the feasibility and validity of the proposed optimization design method.

Heavy-Duty Battery Electric Buses’ Integration in Cities Based on Superfast Charging Technologies: Impact on the Urban Life

As part of this work, several Battery Electric Buses (BEBs) of 9 m, 12 m, and 18 m lengths and superfast chargers based on a pantograph of up to 600 kW were developed and demonstrated in selected European cities. In Osnabrück (OSN), Germany, superfast charging technologies based on BEBs were demonstrated, and numerous measurement campaigns were conducted. Within the scope of this work, two measurement campaigns are presented, which are related to the impact of BEBs on the urban life, i.e., people’s safety, environment, and users’ comfort. People’s safety was investigated in terms of the electromagnetic emissions emanating from two superfast chargers of 350 kW and 300 kW, as such high charging power during the charging process could be a risk to people’s health and electronics inside and outside the bus. The results showed that the magnetic and electrical emissions are far below the safety standard limits. This confirms that the developed vehicles and chargers in the ASSURED project operate under safe conditions for people in the vicinity of the charging station. Environmental impact and users’ comfort were studied in terms of electric motor noises (compared to diesel engines), power electronic devices and their cooling, contact noises of the pantograph, and vibration inside the BEBs compared to diesel buses. It was found that, in most cases, the outside noise emission of BEBs are significantly lower than the noise emissions emitted by diesel buses. Considering the inside noise emissions in the passenger’s section, all BEBs showed lower Sound Pressure Levels (SPLs) in comparison to the diesel busses. As a second part of the ride comfort, vibrations inside BEBs are on the same level as some diesel buses but are mostly significantly lower. All charging processes (pantograph operation and charging process) have a slight noise emission, with 64.6 dB(A) and 52.3 dB(A), respectively, when comparing the engine noise at the departure of the tested diesel buses with 70.8 dB(A) to 80.4 dB(A). Overall, a reduction in noise emissions and an improvement in the ride comfort were observed for the BEBs compared to diesel busses. The objective of this brief study is to provide bus operators, decision-makers, urban planners, and authorities with an overview of the benefits of BEBs for cities and to help them understand the various infrastructural impacts on urban areas and improve the quality of services.

Research on Anti-DC Bias and High-Order Harmonics of a Fifth-Order Flux Observer for IPMSM Sensorless Drive

Due to various nonideal factors, including the motor parameter mismatches, detection errors, converter nonlinearities, noise, etc., dc bias and high-order harmonics exist in the flux model, which make the traditional flux observer estimation inaccurate. In order to suppress dc bias and high-order harmonics, an interior permanent magnet synchronous motors (IPMSM) sensorless drive method based on a fifth-order flux observer (FOFO) is proposed in this article. The proposed FOFO can completely remove dc bias and has a strong filtering ability for high-order harmonics. Additionally, the parameters of the FOFO are set through the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</i> -domain analysis. Then, the discrete FOFO is obtained for better implementation in digital systems. The proposed FOFO is verified by experiments on a 2.0-kW IPMSM drive platform.

Prediction of Automobile Wiper Motor Noise Based on Support Vector Machine with Vibration Sensors.

Wiper motor noise has an important impact on vehicle comfort. Accurate prediction of wiper motor noise can obtain motor NVH performance in motor manufacturing or earlier stage and provide necessary support for NVH performance design of parts and vehicles. However, the prediction accuracy of wiper motor noise by the traditional CAE or testing method is low. Data-driven technology provides a new idea for wiper motor noise prediction with its advantages of high efficiency and high precision. This paper studies the wiper motor noise prediction algorithm based on the motor vibration signal, respectively, using the transmission path analysis theory and the support vector machine theory, and carries on the test verification and comparative analysis of the effect. The results show that the method based on support vector machine is more accurate in the prediction of wiper motor noise and has higher practical engineering value.