Analytical Modeling of High-Torque-Density Spoke-Type Permanent Magnet In-Wheel Motor Accounting for Rotor Slot and Eccentric Magnetic Pole

Kong, Xiangping; Hua, Yuntao; Zhang, Zhuoran; Wang, Chen; Liu, Ye

doi:10.1109/tte.2021.3078449

Cited by 21 publications

(5 citation statements)

References 27 publications

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“…The tangential magnetic circuit design of rotor provides a significantly enhanced magnetic concentration effect, while FSCW has a lower slot-per-pole ratio than distributed winding, which significantly improves the air-gap magnetic density and increases the average torque. Compared to conventional spoke-type PM motors or derivations with eccentric poles used by previous study [6], [17], [19], the machine has auxiliary notches (ANs) to adjust the rotor magnetic circuit and linearly changes part of the air-gap length along the circumferential direction, equivalently adjusting the air-gap magnetic density to make it more sinusoidal, thus reducing harmonics (Fig. 1(a)).…”

Section: Initial Machine Topology and Specificationmentioning

confidence: 99%

“…Compared to the FE, the analytical model, such as magnetic equivalent circuit (MEC) model and sub-domain model, does have a considerable advantage in the computing process. Still, there is a problematic trade-off between computational accuracy and pre-maintenance workload [15]- [17]. Among the previous research, the study objects are generally consisting of a parametric solution model or a mathematical model that indirectly reflects the solution of multi-objective design and optimization.…”

Section: Introductionmentioning

confidence: 99%

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Fast Design of Spoke-Type PM Motor With Auxiliary Notches Based on Lumped-Parameter Magnetic Equivalent Circuit Model and Hybrid Multiobjective Optimizer

et al. 2022

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The multi-objective design of PM motor is time-consuming. The accuracy complexity of the solver model and the efficiency of the optimizer affect the cycle of electromagnetic design. A fast design method of spoke-type PM motors with auxiliary notches based on lumped-parameter magnetic equivalent circuit (MEC) model and a hybrid multi-objective optimizer (HyMOO) are proposed in this article. The MEC model is established to quickly reflect the influence of design parameters on electromagnetic and torque performance in the account of auxiliary notch structure in the rotor lamination. Meanwhile, an HyMOO is proposed considering the Grey Wolves Optimization (GWO) model, to solve more complex multimode problems involving more parameters. The accuracy and high calculation speed of the proposed MEC are verified in comparison with the FE method. A benchmark test by general distance (GD) and inverted generational distance (IGD) proves the HyMOO with better converge speed and robustness. Based on the MEC model and HyMOO, a fast electromagnetic design is applied for the motor with requirements of 140Nm rated torque and 4.5% torque ripple. The optimal solutions are validated by FE analyses, and the best design are chosen, manufactured as prototype, and tested. Both the FE and experimental analyses verify the reliability of the fast design and the proposed motor.INDEX TERMS Auxiliary notch, fast multi-objective design, multi-objective optimizer, lumped-magnetic equivalent circuit model, spoke-type permanent magnetic machine

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Section: Initial Machine Topology and Specificationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fast Design of Spoke-Type PM Motor With Auxiliary Notches Based on Lumped-Parameter Magnetic Equivalent Circuit Model and Hybrid Multiobjective Optimizer

et al. 2022

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“…Compared with the finite element model, the magnetic field prediction model obtained using the equivalently split method has high accuracy. In [16], a hybrid analytical model combining the subdomain method is presented. The rectangular spoke magnets, eccentric magnetic poles, and rotor slots are approximated using multiple layers of ideal arc-shaped subdomains.…”

Section: Introductionmentioning

confidence: 99%

Novel Magnetic Field Modeling Method for a Low-Speed, High-Torque External-Rotor Permanent-Magnet Synchronous Motor

Kou,

et al. 2023

Electronics

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In view of the unstable electromagnetic performance of the air gap magnetic field caused by the torque ripple and harmonic interference of a multi-slot and multi-pole low-speed, high-torque permanent magnet synchronous motor, we propose a simplified model of double-layer permanent magnets. The model is divided into an upper and a lower subdomain, with the upper subdomain being an ideal circular ring and the lower subdomain being a segmented sector ring. Moreover, we develop an exact analytical model of the motor that predicts the magnetic field distribution based on Laplace’s and Poisson’s equations, which is solved using the method of separating variables. Taking a 40p168s low-speed, high-torque permanent magnet synchronous motor as an example, the accuracy of the model is verified by comparison with an ideal circular ring model, a segmented sector ring model, and the finite element method. Based on the proposed simplified model, three combined permanent magnets considering both edge-cutting and polar arc cutting structures are proposed, which are chamfered, rounded, and rectangular combinations. Under the premise of a consistent edge-cutting amount, the electromagnetic characteristics of the three combination types of permanent magnets are compared using the finite element method. The results show that the electromagnetic characteristics of the chamfered combination PM are superior to those of the other two combinations. Finally, a prototype is manufactured and tested to validate the theoretical analysis.

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“…To improve the torque density of the spoke-type PM motor, the design-based or control-based strategies can be used. At the control level, for higher torque densities, the rated current is usually set to the current value at the maximum current density, and higher current will burn out the motor windings [12]- [13]. Therefore, the improvement of torque density is equivalent to seeking a higher torque per ampere (TPA).…”

Section: Introductionmentioning

confidence: 99%

Torque Improvement of Spoke-type Permanent Magnet Motor with Auxiliary Stator Using Harmonic Current Control Strategy

Zhao

et al. 2023

Trans. Electr. Mach. Syst.

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The spoke-type permanent magnet motor with auxiliary stator exhibits high torque performance owing to the flux focus effects. To further improve its torque density, this paper proposes a control method by using harmonic current strategy. Based on the theoretical analysis, a 3-D torque look-up table by dq-axis current and electrical angle is established with the aid of the finite element method (FEM). The maximum torque per ampere curve at each rotor position is identified and summarized to adequately indicate the relationship between torque and current amplitude of the motor. Through theoretical derivation, it is concluded that the minimum torque cost curve is the contour line of ∂Te/∂i 2 , which can be employed to identify the harmonic current for torque density improvement. Compared to traditional strategies, the proposed control strategy can increase torque density of forward and reverse torque by 1.22% and 1.40%, respectively. The experimental results verify the analysis and simulation results, as well as prove the effectiveness of the proposed strategy.

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Analytical Modeling of High-Torque-Density Spoke-Type Permanent Magnet In-Wheel Motor Accounting for Rotor Slot and Eccentric Magnetic Pole

Cited by 21 publications

References 27 publications

Fast Design of Spoke-Type PM Motor With Auxiliary Notches Based on Lumped-Parameter Magnetic Equivalent Circuit Model and Hybrid Multiobjective Optimizer

Fast Design of Spoke-Type PM Motor With Auxiliary Notches Based on Lumped-Parameter Magnetic Equivalent Circuit Model and Hybrid Multiobjective Optimizer

Novel Magnetic Field Modeling Method for a Low-Speed, High-Torque External-Rotor Permanent-Magnet Synchronous Motor

Torque Improvement of Spoke-type Permanent Magnet Motor with Auxiliary Stator Using Harmonic Current Control Strategy

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