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Cogging torque generation mechanism (a) distribution of magnetomotive force due to permanent magnet rotation of motor (①-⑤ timeline) (b) cogging torque due to permanent magnet rotation of motor.
Source publication
This paper presents a method for reducing the cogging torque for a sloping notch with two notches applied on the stator teeth. The accuracy of FEA was confirmed by a comparison with a previous model using an asymmetric notch for the experiment data and 3D FEA results, followed by a comparison of the cogging torque of a two notches model and a slopi...
Contexts in source publication
Context 1
... the case of a BLDC motor, a permanent magnet is used for generating a magnetic field, which inevitably has a cogging torque as shown in Figure 1. Cogging torque stand for the force generated to return to the balanced state when the position of the core and the magnet moves to the position where the magnetic field is unbalanced while the motor rotates. 1 -5 in Figure 1a shows a number according to the passing of time. ...
Context 2
... the case of a BLDC motor, a permanent magnet is used for generating a magnetic field, which inevitably has a cogging torque as shown in Figure 1. Cogging torque stand for the force generated to return to the balanced state when the position of the core and the magnet moves to the position where the magnetic field is unbalanced while the motor rotates. 1 -5 in Figure 1a shows a number according to the passing of time. The cogging torque acts as a torque that hinder with the generation of torque in the desired rotational direction in both the motor that operates when is supplied of electric power and the generator that generates power when the rotor rotates. ...
Context 3
... in the case of single-phase BLDC motor, when the poles and slots are symmetrically designed as shown in Figure 2, the rotor is aligned at the position where the force is balanced, so even if it is excited, the initial start is unstable. Therefore, it is common to design the shape of the stator or rotor asymmetrically in order to align the initial rotor Figure 1. Cogging torque generation mechanism (a) distribution of magnetomotive force due to permanent magnet rotation of motor ( 1 -5 timeline) (b) cogging torque due to permanent magnet rotation of motor. ...
Context 4
... the result of the constraint on the optimization result needs to be confirmed. Figure 10 analyzes the characteristics of the optimization model using FEA. As a result, of the optimal design, the size and position angle of notch (a) were 2 • and 1.2162 mm, respectively, and those of notch (b) were 11.0925 • and 0.5 mm, respectively. ...
Context 5
... the result of the constraint on the optimization result needs to be confirmed. Figure 10 analyzes the characteristics of the optimization model using FEA. ...
Citations
... Different slew rates for two incoming and outgoing phases arise due to the inductance, which leads to current ripples during the CZ, as shown in Figure 1. The electromagnetic torque is harmed by the current ripples, which also cause mechanical vibration and auditory noise [8][9][10]. To overcome these limitations, different types of pulse width modulation (PWM) techniques have been proposed which are quite complex and not cost-effective [11]. ...
... The major concern with this topology is that the occurrence of current ripples due to the commutation, in addition to diode freewheeling, is not discussed. The electromagnetic torque is harmed by the current ripples, which also cause mechanical vibration and auditory noise [8][9][10]. To overcome these limitations, different types of pulse width modulation (PWM) techniques have been proposed which are quite complex and not cost-effective [11]. ...
... If VS = 4Em, then the motor speed is equal to the actual value which means that the i2 current gains a steady-state position when i1 decreases to zero, as presented in Figure 3c. Hence, the commutation finishes at the same time, which causes zero torque ripple [8]. ...
Although brushless direct current motor (BLDCM) drives are becoming more popular in industrial and commercial applications, there are still significant difficulties and unresolved research issues that must be addressed. In BLDCM drives, commutation current ripple (CCR) and diode freewheeling during non-commutation zone (NCZ) are the major challenges. To overcome these limitations, this paper proposes a novel PWM-Model Antiseptic Control (PWM-MAC) technique to alleviate the freewheeling of the diode. The proposed PWM technique is used to alleviate the diode freewheeling in the NCZ, whereas the DCLV circuit is utilized to obtain variable DC-link voltage to address the CCR in the CZ. The MATLAB/Simulink results are included along with experimental results obtained from a laboratory prototype of 325 W. The proposed module reduces the current ripple by 31.7% and corresponding torque ripples are suppressed by approximately 32.5%. This evidences the performance of the proposed control technique.
... In [10], the torque ripple was reduced by applying a notch to the rotor. In studies in which the torque ripple was reduced by applying a notch, circular notches were predominantly used [14]. In this study, an elliptical-shaped notch was applied to determine the torque characteristics of a PMSM based on the width and depth of a notch. ...
Permanent magnet synchronous motors (PMSMs) with rectangular coils in hairpin windings exhibit improved fill factor and reduced end turn of the coils, which in turn improve the efficiency and power density of PMSMs, making them ideal for e-mobility applications. Herein, the shape of a PMSM was optimized for torque ripple reduction using metamodels to improve the noise and vibrational performance of the motor. The objective function of the optimal design aimed to minimize the torque ripple, and the average torque and efficiency were set as constraints. The notch width and depth and barrier length were selected as the design variables to satisfy the objective function and constraints. Using the optimal Latin hypercube design technique, 27 experimental points were selected, and a finite element analysis (FEA) was performed for each point. Furthermore, a function approximation was performed using six metamodels, and the best metamodel was selected using the root mean square error test. Moreover, the optimization was performed by combining the best metamodels for each variable with a sequential two-point diagonal quadratic approximation optimization algorithm. The torque ripple was improved by approximately 1.63% compared with the initial model, whereas the constraint values remained constant. Finally, an FEA was performed on the optimal point, and the FEA results matched with those of the optimal method.
In recent years, the demand for electric vehicles in the market has increased in an era of technological progress aimed at zero emissions to the environment. It explored the tremendous range of improvements for electric vehicles from a technical and commercial perspective. However, these electrification trends have revealed various problems associated with them. Above all, ride comfort and vehicle durability are very important concerns for users. Vehicle-specific vibration noise has a significant impact on ride comfort and battery life. This white paper provides an overview of noise and vibration analysis for electric vehicles. The first and most important introductory section provides an outlook on the growing demand for electric vehicles and the rapidly growing market and types of electric vehicles. The second section provides an overview of EV noise and vibration sources and a review of the supporting literature. In the third section, we will look at different techniques for vibration sources. From traditional techniques to cutting-edge techniques. Finally, we draw overarching conclusions along with some future research areas.
