H. Lin

A new Halbach arc permanent magnet synchronous motor with three-dimensions air gap used on large telescope

This paper proposes a new arc permanent magnet synchronous motor (APMSM) with three-dimensions (3-D) air gap. The proposed APMSM includes one rotor and four segmental stators which cores and windings are type C. A 3-D air gap, which is formed by C-type stator and rotor, provides a large air gap area which makes APMSM have higher torque density than that of 2-D conventional arc motor. Halbach permanent magnet (PM), which can reduce torque ripple, is disposed in rotor. The proposed and another two APMSMs are analyzed by finite element method. The characteristics of proposed APMSM, high torque density and low torque ripple, are verified by the computed results.

A novel consequent-pole hybrid excited vernier permanent-magnet machine for EV/HEV applications

Vernier Permanent-magnet machine (VPMM) has been recognized in recent years as a substitute for permanent magnet synchronous machines (PMSM) in direct-drive applications such as wind turbine generators, motorcycles and electric vehicle/hybrid electric vehicle (EV/HEV) [1].

Thermal analysis of consequent-pole hybrid vernier permanent-magnet machine for EV/HEV applications

Since vernier permanent-magnet machine (VPMM) has the merit of low-speed operation with high output torque due to the “magnetic-gearing” effect [1], they have been used in the direct-drive applications such as wind power generator, electric vehicle/hybrid electric vehicle (EV/HEV) [2,3].

Modular dual three-phase fractional-slot overlapping windings for reducing rotor losses of permanent magnet synchronous machines

Due to high torque density, low torque ripple, high efficiency, excellent fault-tolerance capability and convenient manufacturing, fraction-slot concentrated windings (FSCWs) are desirable to be used in high performance permanent magnet (PM) synchronous machines.

Cogging torque optimization of a novel transverse flux permanent magnet generator with double C-hoop stator for wind power application

Transverse flux permanent magnet generator (TFPMG) is especially suitable for wind power application for the merits of large pole numbers, decoupled magnetic circuit, and high power density. The distinguishing feature of TFPMG is the magnetic flux existed in three-dimensional space and three-dimensional finite element method (3-D FEM) is employed to analyze its characteristics. Such as flux-switching TFPM generator [1], many TFPMGs with new topologies have been proposed. However, they commonly have a drawback that only half of PMs do work at the same time and the cogging torque vibrations are unacceptable and desiderated to be optimized. The proposed 12 pole-pairs TFPMG overcomes these shortcomings, which schematic structure is shown in Fig. 1 (a). The generator is constructed by the double C-hoop stator cores inserted into machined cavities in the stator holder, the doubled PMs screwed onto two rotor disks with opposite polarities to enable the flux-concentrated effect, and the armature winding bundling all stator hoops.

A novel transverse flux permanent magnet generator with double C-hoop stator for wind power generation

Transverse flux permanent magnet generator (TFPMG) has attracted a great attention for the large torque and high efficiency at low speed, as well as the prominent capability of carrying considerable pole numbers. Many new TFPMGs with attractive structures have been proposed such as a novel flux switching transverse flux PM generator (FS-TFPMG) presented to improve the stator space utilization by arranging more stator cores and to increase the flux density in the air-gap by adopting the novel topology. A disk-shaped structure TFPMG is constructed and optimized by laminated steel sheets and circular flat shaped permanent magnets. This paper proposes a distinguishing double c-hoop stator TFPMG, which has better utilized stator space and nearly half of the armature winding and PMs of the traditional double-side ones. Benefited from the merits of its low speed and high torque the proposed TFPMG is suitable for wind power generation.

Torque characteristics of dual stator permanent magnet vernier machine with different pole/slot combinations

Traditional direct-drive permanent magnet synchronous machine (PMSM) suffers from large bulk and complex topology structure, which extremely limits its industrial applications. As a novel embranchment of PMSM, PM vernier machine (PMVM) incorporates the magnetic gear effects into conventional PMSM producing high torque at a relatively low speed, which is desirable for direct-drive applications. Recently, the specific magnetic field modulation effect and high output torque ability have been subtly incorporated into PMVM, which simultaneously enables the sinusoidal back-EMF waveform, high power density, efficient thermal dissipation. However, the torque characteristics of PMVMs with different pole-slot combinations and gear ratios have not been studied systemically as yet. In this paper, two representative dual stator PMVMs are designed to analyze the torque characteristics in detail with particular emphasis on the dominant influence of pole-slot combinations. In addition, gear ratio selecting is also investigated through the analysis of the electromagnetic characteristics of the designed PMVMs, which provides further unique insights into the design and optimization of PMVMs.

Detent force minimization of a novel linear-rotary permanent magnet actuator with independent magnetic circuit structure

The paper proposes a novel linear-rotary permanent magnet actuator (LRPMA) with independent magnetic circuit structure, which can decrease the coupling relationship between the permanent magnet flux path and armature flux path, and of the adjacent phases. The thrust force of the LRPMA can be improved by changing the distance between the stator segments in the axial direction. A 3D ideal model is built for analyzing the magnetic flux density and a simplified model of one section for thrust force calculation is built, and the expression of cogging force, end force, normal force are derived by analytic method and Maxwell stress tensor method. The simulated results show that the detent force can minimized when the distance between the stators in axial direction, which has the similar results of that analyzed by finite element method.

A flux-concentrating external-rotor switched flux hybrid magnet memory machine for direct-drive automotive applications

In this paper, an external-rotor switched flux hybrid switched flux memory machine (ER-SF-HMMM) with effective flux-concentration is developed. Due to external-rotor configuration, the stator design space is enlarged, and hence the geometric compromise existed in internal rotor (IR) counterpart is resolved. Thus, the proposed ER-SF-HMMM can perform higher torque capability and flux adjustability than the IR one. In addition, since the current pulses are energized to perform the online magnetization of low coercive force (LCF) PMs, the associated excited loss is eliminated. Therefore, high efficiency operation within a wide range of speeds and loads can be achieved. The machine topology evolution, operating principle and the distinct features are addressed and highlighted. Then, the electromagnetic performance of ER-SF-HMMM is investigated and quantitatively compared with that of its IR counterpart, which confirm the theoretical analyses.

Quantities comparative analysis of a linear-rotary permanent magnet actuator with HTS field winding

A linear-rotary permanent magnet actuator (LRPMA) is proposed with HTS field winding placed in the inner stator. The current in the HTS field winding can generate higher exciting field than that of common armature winding. A topology without HTS field winding and another topology with single direction permanent magnet mounted on the surface of the mover are proposed in order to compare the electromagnetic properties. And the electromagnetic characteristics and the corresponding harmonic analysis of the three topologies are analyzed by finite element method, the proposed LRPMA can offer higher torque density and force density than those of the other two topologies, while the cogging torque and cogging force are increased a little.