Applied Mechanics and Materials Vols. 416-417

Abstract: A simple analytical method is developed to design novel axial field flux-switching permanent magnet (AFFSPM) machines in terms of back electromotive force (back-EMF) and cogging torque. The machine is proposed with E-shaped laminated segments in the stator. Some major parameters are originally designed with reference to those of a 12/10-pole U-core AFFSPM machine, including the rotor tooth width, the split radio of the inner diameter to outer diameter of the stator and the stator parameters. In this paper, they are investigated and optimized for attaining essentially sinusoidal back-EMF and low cogging torque by 3-D finite element method (FEM). Compared with 12/10-pole AFFSPM machine, it is shown that the volumes of magnets are almost reduced by 30%, while the similar output torque at the rated current can be obtained, and the ratio of the mutual-to self-inductance is largely reduced, which indicates the proposed motor has better fault-tolerant capability.

Abstract: This paper presents a novel linear switch reluctance machine (LSRM) with segmental stator. The principle of the presented machine is given and compared to the well-known teeth type linear switch reluctance machine. Because the presented machine incorporates a simple concentric winding and concrete ferrite-magnetic segmentations, it features unique magnetic circuit compared to teeth type linear reluctance machine. It is found that the presented linear reluctance machine gains favorable superiority over the teeth type linear reluctance machine in terms of high force density, high reliability and low cost. Different topologies of the presented machine are given and both their merits and demerits are discussed.

Abstract: Magnetic hysteresis effects, present in the force of an E-core reluctance actuator, are examined by simulations and measurements. Simulations have been performed with a 3d finite element method (3d-FEM) and a Preisach model, which is extended with a dynamic magnetic equivalent circuit (MEC) model. Both simulation methods are first examined on the prediction of the magnetic flux density in a closed-and open toroid for dc-and ac excitations. Finally, both methods are used to predict the force of the E-core reluctance actuator, which is compared to ac force measurementsperformed with a piezoelectric load cell.

Abstract: For the design and analysis of a linear electrical motor, an analytical solution of electric and magnetic fields is barely achieved with the required accuracy, due to the end and edge effects, and the nonlinear characteristic of the materials. Optimal design with the finite element models (FEM) is often expensive, in terms of the computation time. The space-mapping techniques allow having an affordable computation cost with a minimum number of computationally expensive FEM evaluations. In this paper, based on a kriging model, a 2D FEM and a 3D FEM, a 3-level adapted output space-mapping technique is employed. The results show that the proposed algorithm allows saving a substantial amount of computation time compared to conventional 2-level output space-mapping technique.

Abstract: This paper proposes a new type of linear motor based on the concept of variable flux reluctance motor (VFRM). By adopting segmented primary stator, the segmented linear VFRM (SLVFRM) can eliminate asymmetry between phases due to end-effect. Meanwhile, multi-phase SLVFRM of any number of phases can be obtained by adjusting number of segments directly. The stator/mover tooth pitch combination and segments arrangement rules are also illustrated. An optimized 3-phase SLVFRM is analyzed by finite element analysis, with focus on characteristics such as cogging force, back-EMF and winding inductances. Further, both brushless AC (BLAC) and brushless DC (BLDC) drive for SLVFRM are investigated. Besides much smaller force ripple, BLDC drive can obtain higher average force at same RMS current due to trapezoidal back-EMF. The force characteristicwith variousAC and DC currents and current angles are also investigated in the paper, and it shows that SLVFRM has negligible reluctance force while keeping the same AC and DC currents is optimal for maximum efficiency operation under a fixed copper loss.

Abstract: Long stroke linear motor has an unparalleled advantage in the field of long-distance transport, transfer and electromagnetic launch system. The paper presents a primary segmented permanent magnet linear synchronous motor (PS-PMLSM), which can solve the problems of the long stroke linear motor in excessive power dissipation, the difficulties of power supply. According to the motor structure characteristics and application background, the paper proposes four feasible strategies--a single inverter series alternating power supply (SISAP), a single inverter parallel alternating power supply (SIPAP), dual inverters alternating power supply (DIAP) and inter-segment optimal power supply (ISOP). Firstly, the article makes studies on those strategies from the economic cost, energy efficiency, the complexity of switching among the segments and the convenience of algorithm application by calculation and simulation. Secondly, the mathematics model of the motor and control system model is deduced from different strategies, respectively. Then, the available control method is derived from the analysis of these models and the motion characteristics. Finally, effects of performance are comparatively analyzed through the simulation.

Abstract: A novel brushless compound-structure permanent-magnet synchronous machine (CS-PMSM) based on the magnetic field modulation principle is proposed for hybrid electric vehicles. As the key part of the brushless CS-PMSM, the operation principle of the electromagnetic planetary-gear machine (EPGM) is investigated by analytical method. The magnetic-field distribution and torque performance of the EPGM are studied by finite-element method (FEM). To obtain the optimal design scheme, the influence of the span ratio and thickness of the magnetic block and the slot-opening on the electromagnetic performance is investigated. Finally, the core loss distribution of the EPGM is investigated and the performance of this machine is fully evaluated.

Abstract: In this paper, an integrated winding structure short-stroke DC planar motor is studied. The integrated winding structure and non-integrated winding structure are compared and two types of coil arrangements are proposed. Then, static characteristics analysis and structural optimization are made by using FEM. The influences of the main parameters on the electromagnetic force are analyzed respectively based on the finite element simulation.

Abstract: The proposed magnetic circuit precisely evaluates magnetic fluxes between the field magnets of dual Halbach arrays. In the case that an actuator is configured with the dual Halback arrays and the armature coils between them, the air gap length between the dual Halbach arrays gives the maximum number of interlinkage magnetic fluxes with the armature coil through algebraic approach. The new design method is on the basis of the proposed magnetic circuit. This method makes it clear that the air gap length should be more than 1.2 times longer than the permanent magnet poles length. The utility of this design method is verified through designing cylindrical linear synchronous motor provided with the dual Halbach arrays.

Abstract: The conventional linear PM machines can be classified into the type which has armature on mover or the type which has it on stator. In either type it requires to lay the armature windings or the permanent magnets over a long distance in the application for long distance movement. It leads to high cost. Therefore, we proposed a linear vernier machine with the magnets only on armature side. This paper describes the theoretical proof and introduces comparisons of computed and experimental results. The comparisons agreed well. The prototype machine for the experiment had a problem due to less accuracy in assembly but we think it is not difficult to solve the problem.