Permanent Magnet Part Research Articles

Investigation of a Parallel Hybrid Excitation Machine With Auxiliary Winding for Loss Reduction in Flux-Weakening Operation

An axial-parallel hybrid excitation machine (APHEM) with an auxiliary winding is proposed and investigated for loss reduction in the flux-weakening operation. The permanent magnet (PM) flux and wound field flux of the APHEM are different and coupled under the armature action. Based on the axial-parallel structure, an auxiliary winding is introduced into the PM part to make better utilization of the distinct PM flux. Because of the coupling of the two fields, this auxiliary winding not only couples the PM flux but also affects the wound field flux. Two major conclusions can be derived from the theoretical analysis. Firstly, the auxiliary winding couples the PM flux and produces extra torque, benefiting a smaller field current. Secondly, the auxiliary winding can suppress the phase voltage because of the larger characteristic current of the PM part than the wound field part. This facilitates a smaller d-axis armature current. The reduced currents favor the reduction in copper loss and core loss. Compared with the original APHEM under the minimum-copper-loss control, the proposed method achieves a 34% reduction in the maximum loss and a 60% decline in the maximum torque ripple ratio. Finally, the measured results verify the analysis.

Optimal Design and Performance Analysis of Dual-Stator Permanent Magnet Fault-Tolerant Machine

This article presents the optimal design of a dual-stator permanent magnet fault-tolerant machine (DSPMFTM). In order to enhance the torque density, the radial-flux dual-stator structure is expanded to redundant situation. The parallel rotor is proposed to add self-inductance for realizing limited short-circuit current, and thus, the deep and narrow notches (DNNs) are replaced with large-opening slots. The optimal design of DSPMFTM is raised in this article because of the more complexity of flux coming from the short distance between the reluctance part (RP) and the permanent magnet part (PMP). The influences of slot opening, separating distance between PMP and RP along with permanent-magnet shape, are considered. Also, the varieties of torque density, ratio of mutual inductance to self-inductance, and short-circuit current to rated value are examined. A prototype is designed and manufactured according to the optimization results. The experimental results are coincident with the simulations, indicating that the DSPMFTM has a better performance in torque density and fault tolerance.

Electromagnetic Torque Performance Analysis of a Parallel Hybrid Excitation Machine With Axial Paralleling of Permanent Magnet Part and Variable Reluctance Part

In this paper, the electromagnetic torque (EM) performance analysis of a parallel hybrid excitation machine (PHEM) is investigated. It is composed of a permanent magnet (PM) part and variable reluctance part. The flux paths of the two parts are independent and the armature windings are connected in series. PHEM is an axial parallel coupling of two different types of brushless machine. The mechanisms of EM torque for the two parts are quite different and many problems of torque coupling still remain unsolved. A 2-D EM-circuit coupling simulation model is built to analyze the torque characteristics and coupling relationships. The simulation results indicate that the PM part plays a main role in the output torque of PHEM. The large inductance ripple of variable reluctance part would cause large torque ripple in PHEM. The target machine is experimentally tested to verify the output torque characteristics. Furthermore, the torque-angle characteristics are studied with different field current and it shows that the best load angle could be around 110° to get maximum output torque and relatively smaller torque ripple.

Hybrid Synchronous Motor Magnetic Field Analysis

This paper introduces researching results of hybrid synchronous motor rotor permanent-magnet part magnets’ magnetization influence on its starting torque. The magnetic field analysis is made in reluctance synchronous motor and synchronous permanent-magnet motor, as main parts of the hybrid motor.

Finite Element Analysis and Experimental Study for MWD Hybrid Excitation Generator

To obtain the stable output voltage, a new type of MWD hybrid excitation generator is designed in which magnetic flux can be regulated from -2% to 22%. In the generator, hybrid excitation part and permanent magnet part work in parallel. This article introduces the working principle and structure of this generator. In addition, finite element analysis, magnetic field and regulation characteristics analysis for this generator is addressed to illustrate the variation of magnetic flux with pole length and excitation current changing. Experiments verify the design and finite element analyses.

Design of New Type Synchronous Motor Based on the Stability

New type synchronous motor is made of a permanent magnet part and a reluctance part, there are import influence for the motor performance by the variable k, the fraction length of the permanent magnet part, and α, the displaced angle between the two part d-axis. The math model is derived based on Lyapunov stability, searching the appropriate k and α value, plotting stability regions, giving the simulation results. The calculation results are verified by simulation results.

Open Loop Stability on Hybrid Synchronous Motor

This paper searched open loop stability on hybrid synchronous motor which is made of a permanent magnet part and a reluctance part, there is important influence for the ratio k, the fraction length of the permanent magnet part, and the displaced angle α, the between the two part d-axis, the small-signal mathematics model was derived based on d-q reference frame, and optimized the appropriate k and α value considering the stability and the harmonic distortion factor (THD), The simulation results show that the model is correct.

Finite Element Analysis of Actuator for Active Vibration Isolation System

用于空间科学实验的主动振动隔离系统采用洛伦兹力驱动的方法, 将被隔振的平台 悬浮于空中. 对电磁驱动部分的动力学分析是各种设计和实验的基础. 提出了一种驱动器的结构, 并对驱动器的永磁部分进行了有限元分析, 包括模型的建立、 静力学分析、模态分析、瞬态分析、谐响应分析和谱分析, 由此验证其力学性能可以 满足设计要求. 为优化结构设计, 减小驱动器尺寸, 降低设计开发成本, 缩短设计开发周期, 提高产品质量奠定了基础.

New approach to longitudinal magnetic field in drum type machine

Without 3D analysis, the longitudinal distribution of the magnetic field in a drum-type electric machine can be determined two-dimensionally, provided that radial results, fundamental components of the air gap flux density related to each axially-separated part, are obtained in advance by any conventional 2D numerical method. Details on the new approach, including how to bound the domain, how to represent the problem and how to solve it, are presented. As an application, a new type of synchronous machine with a two-part rotor, having a surface permanent magnet part and an axially-laminated anisotropic reluctance part axially-separated on the same shaft, is investigated, with obvious high computational economy and improved accuracy.