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This paper describes a five-phase fault-tolerant modular in-wheel permanent-magnet synchronous machine (PMSM) for electric vehicles. By adopting both the analytical and finite-element methods, the magnetic isolation abilities of some typical slot/pole combinations are analyzed, and a new fractional-slot concentrated winding topology that features hybrid single/double-layer concentrated windings and modular stator structure is developed. For the proposed hybrid single/double-layer concentrated windings, feasible slot/pole combinations are studied for three-, four-, and five-phase PMSMs. A five-phase in-wheel PMSM that adopts the proposed winding topology is designed and compared with the conventional PMSM, and the proposed machine shows advantages of large output torque, zero mutual inductances, low short-circuit current, and high magnetic isolation ability. Some of the analysis results are verified by experiments. [ABSTRACT FROM AUTHOR]

This paper describes a tubular dual-stator flux-switching permanent-magnet (PM) linear generator for free-piston energy converter. The operating principle, topology, and design considerations of the machine are investigated. Combining the motion characteristic of free-piston Stirling engine, a tubular dual-stator PM linear generator is designed by finite element method. Some major structural parameters, such as the outer and inner radii of the mover, PM thickness, mover tooth width, tooth width of the outer and inner stators, etc., are optimized to improve the machine performances like thrust capability and power density. In comparison with conventional single-stator PM machines like moving-magnet linear machine and flux-switching linear machine, the proposed dual-stator flux-switching PM machine shows advantages in higher mass power density, higher volume power density, and lighter mover. [ABSTRACT FROM AUTHOR]

The magnetization processes in nanostructures samples, based on the magnetoelastic effect, are characterized by acoustic internal friction measurements using the vibrating-reed technique. It was observed that the magnetoelastic effect in nanostructures rare earth-transition metal (RE-TM) film increases with an increase in grain size.

The electrocaloric effect of BaTiO3 multilayer thick film structure was investigated by direct measurement using differential scanning calorimeter. The samples show a giant electrocaloric effect of 0.89 J/g under E=176 kV/cm, which also depends on the varying rate of applied field, following a general power-law relation. Based on the large net-cooling (0.37 J/g) resulting from the difference in the varying rates of rising and falling fields, the kinetic electrocaloric effect provides a solution for the design of refrigeration cycle in ferroelectric microrefrigerator. [ABSTRACT FROM AUTHOR]

A radial-radial flux compound-structure permanent-magnet synchronous machine (CS-PMSM) is designed and examined. The studies have shown that the stator machine (SM) is slightly saturated with no or little cross-magnetization effect.

A novel axial-axial flux compound-structure permanent-magnet synchronous machine (CS-PMSM), which is used for hybrid electric vehicle (HEV), is integrated by two axial flux disk machines. The results have shown that the CS-PMSM has much higher power density than traditional individual machine and acceptable average torque and torque ripple are obtained by optimizing the pole arc embrace and magnet skewing angle.

A four-quadrant transducer (4QT) electric prototype machine that is radially integrated by two permanent-magnet synchronous machine is manufactured and tested. Results of the load and no-load performance testing of the 4QT indicate that the no-load line-to-line back electromotive force curves are in good agreement with the calculations, thereby verifying the feasibility of the proposed method.

The magnetic properties of nanocrystalline ferromagnets are investigated using simulations at the atomistic and molecular levels. The effect of boundary atoms on the Curie temperature and hysteresis loops was found to be strong and this work provides a systematic approach to atomistic simulation of nanocrystalline ferromagnets, which could be useful for the optimization of magnetic device performance through modification of the interface morphology.

The temperature dependence of the resistivity of nanotubular polyaniline doped with H3PO4 and beta-naphthalene sulfonic acid synthesized by a 'template-free method' are investigated. Based on the results, it is proposed that the nanotube can be described as a 'metallic' bundle of couple chains.

Evolution of Barkhausen jumps during the magnetization reversal process in disordered magnetic material is investigated. The dynamic scaling and inhomogeneous behavior observed in both experiments and theoretical models are discussed.

This paper investigates a novel single-phase flux-switching permanent-magnet (PM) linear machine used for free-piston Stirling engines. The machine topology and operating principle are studied. A flux-switching PMlinear machine is designed based on the quasi-sinusoidal speed characteristic of the resonant piston. Considering the performance of back electromotive force and thrust capability, some leading structural parameters, including the air gap length, the PM thickness, the ratio of the outer radius of mover to that of stator, the mover tooth width, the stator tooth width, etc., are optimized by finite element analysis. Compared with conventional three-phase moving-magnet linear machine, the proposed single-phase flux-switching topology shows advantages in less PM use, lighter mover, and higher volume power density. [ABSTRACT FROM AUTHOR]

The torque density is a key factor for magnetic gears. To obtain maximum torque density, the design principle of magnetic gears is proposed and the maximum transmitting torque is investigated under different combinations of the inner and outer permanent magnets (PM) rotor pole pairs. The research proves that the maximum transmitting torque and the minimum torque ripple can be obtained only when the ratio of the outer and inner PM pole pair numbers is fractional. Then, the optimal selection of the span ratio and thickness of magnetic blocks in the stationary modulating ring is investigated to obtain the maximum torque. Meanwhile, analyses of the losses of various parts in the magnetic gear show that the loss of the PMs is about 70% of the total losses. Therefore, the method of dividing the PM into several pieces along the circumferential direction is employed to reduce the PM loss, which makes the PM loss reduced by 73%. Additionally, the transient behavior of the magnetic gear is analyzed, indicating that the lower torsional stiffness is the main reason for oscillations during transient changes in speed and load. To suppress oscillations due to transients, damper windings are employed and the transient time and the maximum oscillation amplitude are reduced by 25% and 20%, respectively. [ABSTRACT FROM AUTHOR]