Yi Du

Design and Analysis of Linear Stator Permanent Magnet Vernier Machines

This paper presents a new class of linear permanent magnet (PM) vernier machines which is suitable for low speed and high thrust force applications. The machine is composed of a tubular stator and a tubular translator. The stator consists of an iron core with salient teeth wound with 3-phase armature windings and PMs mounted on the surface of stator teeth. The translator is designed as a simple tubular iron core with salient teeth so that it is very robust to transmit high thrust force. By using the finite element method, the characteristics and performances of the proposed machine are analyzed and verified.

A Linear Stator Permanent Magnet Vernier HTS Machine for Wave Energy Conversion

In this paper, a new linear stator permanent magnet (PM) vernier high-temperature superconductor (HTS) machine is proposed for wave energy conversion. The machine adopts a double-sided design and inner-translator arrangement where the stator consists of two plane iron cores with salient teeth wound with 3-phase armature windings and PMs mounted on the surface of the stator teeth. While the translator is designed as an iron core with salient teeth on the two sides, the HTS bulks are inset between every two adjacent salient teeth to shield the flux leakage, thus improving the power density of the machine. Based on using the finite element analysis, the characteristics and performances of the proposed machine are assessed. Also, the proposed machine is quantitatively compared with the existing linear stator PM vernier machine. Hence, it validates that its performance, especially the power density, can be improved significantly.

A Linear Doubly-Salient HTS Machine for Wave Energy Conversion

This paper proposes a linear doubly-salient high-temperature superconductor (HTS) machine for wave energy conversion, which is composed of a tubular stator and a tubular translator. Since the translator is a simple iron core with salient poles, it is so robust that it can be directly coupled with the reciprocating buoy. The stator consists of an iron core with salient poles, DC HTS field windings and 3-phase HTS concentrated armature windings. By using the finite element analysis, the proposed machine is quantitatively compared with its permanent magnet and copper-winding counterparts. Hence, it validates that its performance, especially the power density, can be improved greatly.

An improved coaxial magnetic gear using flux focusing

This paper presents a new topology of the coaxial magnetic gear (CMG) in which the permanent magnets (PMs) in the outer rotor are magnetized in tangential direction, hence offering the flux-focusing effect. By using the 2D finite element method, the influence of the main design parameters on the maximum pull-out torque of the proposed magnetic gear is investigated. Also, a quantitative comparison between the proposed topology and the conventional surface-mounted CMG employing radially-magnetized PMs (CMGRM) has been performed and the analysis results indicate that the torque transmission capability of the proposed one can be significantly improved.

Analysis of Linear Flux-Switching Permanent Magnet Motor Using Response Surface Methodology

This paper focuses on the performance analysis of linear flux-switching permanent magnet (LFSPM) motor. The analysis of electrical machines is mostly done by finite element method (FEM) and analytical method. However, it is time-consuming to determine the effects of the design parameters on the motor performance with FEM. It is also difficult to utilize the analytical technique for the intricate structure of LFSPM motor. In this paper, the response surface methodology in conjunction with FEM is proposed to analyze the LFSPM motor efficiently. As a demonstration, the influence of design parameters on the motor net thrust force is analyzed with the proposed method. Analysis of variance and comparison between the fitted response and results obtained from FEM all confirm the validity of the proposed method.

A new coaxial magnetic gear using stationary permanent magnet ring

This paper proposes a new topology of coaxial magnetic gear (CMG) using stationary permanent magnet ring (PMR) between the permanent-magnet (PM) inner rotor and the salient-pole outer rotor without PMs, aiming at improving the robustness of the outer rotor while the torque density is maintained. The fundamental operation of the proposed topology is the modulation of the magnetic field produced by the PMR due to the outer-rotor salient poles, such that appropriate harmonics having the same number of poles as the PM inner rotor can be produced in the inner airgap. By using the finite element method (FEM), the airgap flux density and static characteristics of the proposed CMG are analyzed. Moreover, a quantitative comparison between the conventional CMG and the proposed one is conducted to verify the validity of the proposed design.

Simulation of the Linear Primary Permanent Magnet Vernier machine system for wave energy conversion

The purpose of this paper is to describe a Linear Primary Permanent Magnet Vernier (LPPMV) machine system for direct drive wave energy conversion. Firstly, the structure of the LPPMV machine is proposed and the operation principle of the proposed machine is depicted. Secondly, the mathematical model of the machine is derived based on the three-phase stator coordinate system. Then the control strategy of the maximum energy absorption is discussed. Finally, the simulation model is established based on Matlab/Simulink to investigate the performance of the control system. The simulation results are given to verify the feasibility of the LPPMV machine system for direct drive wave energy conversion.

Theory and comparison of the linear stator permanent magnet vernier machine

The purpose of this paper is to describe a theory study of the linear stator permanent magnet vernier (LSPMV) machine. The fundamental operating principle, design criteria, characteristics and performances of the machine are discussed in this paper. In order to confirm the advantages, a quantitative comparison between the LSPMV machine and the linear vernier hybrid (LVH) machine is performed under the conditions of the same magnetic loading, electric loading and rated speed by using the finite element method. The results show that the proposed machine has higher power density and lower cogging force than the LVH machine.