Conference Agenda

This paper proposes a new heteropolar series-parallel variable flux machine (HSP-VFM) employing the low coercive force (LCF) magnets to play different roles. The LCF magnets are arranged on the q-axis of the proposed machine to perform different functions, which can form either series or parallel magnetic circuits with adjacent high coercive force (HCF) magnets. In the proposed design, the series magnetic circuit ensures the stability of the LCF magnets, while the parallel magnetic circuit enhances the flux-adjusting (FA) capability. The topological evolution process and topology structure of the proposed machine are first introduced. Then, the no-load and on-load characteristics of the proposed machine are evaluated individually, confirming the considerable FA range and torque variation capability. Particularly, the efficiency characteristics of the machine are further evaluated, confirming that the proposed HSP-VFM can achieve overall high efficiency through magnetization state adjustment.

This paper introduces an efficient two-dimensional (2D) method for calculating the leakage inductance of end windings in induction machines, traditionally a three-dimensional (3D) computational challenge. By leveraging a 2D H-formulation, the complex geometry of end windings is transformed into a simplified 2D model. Validation against 3D simulations and experimental results demonstrates very good agreement

Brushless doubly-fed motors are widely used in real life due to their excellent starting and speed regulation performance as well as extremely high safety. In order to better explore the electromagnetic distribution of brushless doubly fed motors under asynchronous operating conditions, this paper uses finite element simulation software to conduct two-dimensional electromagnetic simulation of brushless doubly fed motors. The focus is placed on analyzing the magnetic flux density distribution, the magnetic field line distribution and the air-gap magnetic flux density waveform. On this basis, two motors with different rotor winding forms are established, and a comparative simulation analysis is carried out for the whole process of motor operation. The emphasis is laid on exploring the impact of the rotor winding pitch on the motor operation process.

To reduce the vibration of switched reluctance motor with amorphous alloy core (SRMA), a multi-material topology optimization method based on adding negative magnetostrictive material is proposed in this paper. Firstly, the properties of negative magnetostrictive material are used to the stator core of SRMA to offset the vibration caused by magnetostrictive force and radial electromagnetic force. The Young’s modulus and relative permeability of the core materials in the optimized area are expressed as continuous functions of double design variables. Then, the hybrid-design variables interpolation function is coupled to the multi-material topology optimization to determine the distribution and boundary structure of multiple materials. Considering the computational complexity of multi-dimensional constraints in the optimization framework, the augmented Lagrangian method is used to accelerate the calculation speed. The vibration displacement amplitude of stator core after optimization is reduced by 36%. The calculation time of multi-material topology optimization is reduced by 30%.

The increasing power electronic converters in the power system bring high frequency harmonics, which affect the normal operation of power transformers. The transformer circuit model derived from magnetic circuit conversion has been proved to have good accuracy in transient simulation of power systems, but it cannot reflect the impact of high frequency harmonics on transformers. This paper establishes a high frequency nonlinear transformer topology and proposes a method for quickly calculating model parameters. Parameter inversion can be achieved solely by using the parameters on the nameplate. The magnetic flux is used to invert nonlinear inductance, and the electromagnetic relationship of the transformer is used to invert parasitic capacitance. The proposed fast calculation model is very suitable for power system simulation, as it can effectively reflect the impact of high frequency harmonics on power equipment.

Iron loss is a key factor in machine performance and energy efficiency design. Amorphous alloy (AA) materials are increasingly being widely used in machine design to improve efficiency due to their excellent magnetic properties such as high permeability and low iron loss. However, the magnetic properties of AA can be significantly affected during the manufacturing process, which may lead to magnetic degradation of the material, resulting in a large deviation between predicted and measured iron losses at the machine design stage. Therefore, magnetic property measurement experiments are carried out to investigate the effect of the manufacturing process on the magnetic properties of AA and non-grain-oriented silicon steel (NGO) in this paper. Meanwhile, the iron loss model is improved on this basis, which more accurately reflects the influence of the manufacturing process. Moreover, a finite element model of a permanent magnet synchronous machine (PMSM) is developed to analyze the effect of the manufacturing process on the performance of PMSM. Finally, two prototypes with different stator cores are fabricated and experimentally tested to verify the effectiveness of the above method.

Shaftless Pump-jet Thrusters (SPT) integrates the propulsion motor and impeller, eliminating the traditional propeller's transmission shaft and auxiliary components, resulting in a compact design with high efficiency. However, the stator sleeves usually generate significant eddy current losses under high-frequency alternating magnetic fields. Titanium Matrix Composites (TMCs) exhibit lower electrical conductivity and higher thermal conductivity compared to traditional titanium alloys, making them the ideal substitute for titanium alloy sleeves in motor applications. This paper systematically compares the performance of TA16 and TMCs through comprehensive simulation analysis of motors with diffe

This paper derives the synthesized magnetomotive force of the permanent magnet synchronous motor with unequal tooth and slot structures under both three-phase symmetric and asymmetric currents, and provides the magnetic flux density expression when three-phase symmetric currents are applied. Finite element calculations show that applying three-phase symmetric currents generates reverse rotating magnetomotive force, and the current power angle corresponding to the maximum average output torque is related to the winding configuration. However, applying three-phase asymmetric currents can nullify the reverse rotating magnetomotive force. Using an 8-pole, 48-slot motor as an example, the effects of different winding configurations on the motor's magnetomotive force and output torque are studied, and the optimal winding configuration is presented.

The method of optimizing rotor magnetic pole is usually used to suppress the torque ripple and electromagnetic vibration of PMSM. However, unbalanced magnetic pull and new electromagnetic vibration components may be introduced. This paper proposes a new rotor structure with opposite unequal magnetic poles, and its electromagnetic force wave is systematically analyzed. The symmetrical magnetic poles can avoid the radial unbalanced magnetic pull. Moreover, the general analytical expressions of air gap flux density and electromagnetic force are derived, and the spatial-temporal characteristics of radial electromagnetic force are investigated. Then, the finite element analysis model is established, and the correctness of the theoretical analysis is verified by finite element analysis. The results show that the proposed rotor structure can weaken the related electromagnetic force component, which is conducive to the improvement of the electromagnetic vibration characteristics of the motor.

Vibration and noise in Permanent Magnet Synchronous Motors (PMSMs) have raised concerns due to their potential impact on safety. However, no research currently fully explores the differences in vibration characteristics between the widely used Interior PMSM (IPMSM) and Surface-mounted PMSM (SPMSM) with stator slot skewing from the perspective of electromagnetic analysis. This study investigates the similarities and differences in electromagnetic vibration between IPMSMs and SPMSMs with stator slot skewing. Expressions for the magnetic flux density and electromagnetic force induced by permanent magnets and winding currents are derived for both motor types, revealing that the saliency effect in IPMSMs produces higher-amplitude electromagnetic forces, leading to larger vibrations compared to SPMSMs. However, the spatial and temporal orders of the primary electromagnetic force are the same for both motor types. This conclusion is further confirmed through FEA-based co-simulation.

This paper proposes a novel dual-layer asymmetric series-magnetic-circuit variable flux memory machine (ASMC-VFMM), which combines the series-magnetic-circuit (SMC) structure and the asymmetric permanent magnet (APM) design in an integrated form. Additionally, the use of APM arrangement in the rotor introduces a magnetic-field-shifting (MFS) effect, which effectively addresses the issue of insufficient output torque under the flux-weakened state. Furthermore, the low coercive force (LCF) magnet is adopted in the first PM layer to expand the high-efficiency speed range and the flux changeable (FC) range of the machine. Firstly, the evolution and machine topology of the ASMC-VFMM are introduced. Then, the electromagnetic performance analysis of the proposed machine is conducted using finite element analysis (FEA). Besides, the torque performance of the proposed machine is also compared with a conventional symmetrical SMC-VFMM. The analysis reveals that the proposed machine has a broad FC range and good torque capability under the flux-weakened state.

A novel eddy current loss suppression structure is proposed for the permanent magnet motors based on staggered slotting on the permanent magnet (PM). Compared with the traditional complete segment of the PM, the novel structure can ensure that the shape of PM is orderly. The manufacturing performance of the rotor is improved. Based on analytical derivation and numerical calculations, the effect of the new structure on suppressing eddy current loss is demonstrated. A compensation method for the reduction of PM flux and motor torque caused by slotting is presented. The influence of the new structure on the temperature rise and electromagnetic property of the motor is discussed based on the magnet-thermal coupling analysis.

The axial heat flow in an electric machine with spray-cooled end windings is modelled by a quasi-3D finite-element approach. The approach allows to accurately resolve the cross-sectional winding geometry while efficiently accounting for the temperature gradients in axial direction.