Applied Mechanics and Materials Vols. 416-417

Abstract: Eddy currents induced in a conductor in a changing magnetic field produce a damping force proportional to the heat generated in the conductive material. In this paper, the damping force of short-stroke DC Linear Motor (DCLM) is researched, and then model of damping force is established. In the preliminary work, the analytical expression of magnetic field distribution is obtained by the charge model, so the eddy current inducted in the conductor is calculated. Then the damping force is obtained after the equivalent resistance and inductance of conductors are calculated. The formula of damping force is obtained to optimize damping structure of short-stroke DCLM. The accuracy of damping force model is proved by the experiment.

Abstract: This paper proposes a linear stator perment magnet (PM) vernier machine using variable Halbach Arrays (LSPMV-VHA machine) which offers a number of outstanding merits, such as the high thrust force and low cogging force. The key is to newly employ variable Halbach PM array to substitute the parallel PMs in the linear stator PM vernier (LSPMV) machine. By using the finite element method, the dimensions and the magnetization directions of the PM segments are optimized for the aim of the highest power density. In order to confirm the advantages, a quantitative comparison between the proposed machine and the LSPMV machine is performed in the conditions of the same PM volume, electric loading and rated speed. The results show that the proposed machine has higher power density and lower cogging force than its counterparts.

Abstract: The Inertial Sea Wave Converter is a device that uses the effect of a gyroscope to convert wave energy into electric energy. It is equipped with two Linear Tubular Permanent Magnet Generators. This paper describes the design and optimization processes for a moving-coil linear generator to be installed on the Inertial Sea Wave Converter. FEM Analysis has been performed to validate the design and to optimize forces and generated power. A Power Factor Corrector has been developed as frontend electronics.

Abstract: Recently, an interest in a hybrid system combining only the merits of the conventional wheel-rail system and Maglev propulsion system is growing as an alternative to high-speed maglev train. This hybrid-type system is based on wheel-rail method, but it enables to overcome the speed limitation by adhesion because it is operated by a non-contact method using a linear motor as a propulsion system and reduce the overall construction costs by its compatibility with the conventional railway systems. Therefore, a comparative analysis on electromagnetic characteristics according to the structural combinations on the stator-mover of Linear Synchronous Motor (LSM) for Very High Speed Train (VHST) maintaining the conventional wheel-rail method is conducted, and the structure of coreless superconducting LSM suitable for 600 km/h VHST is finally proposed in this paper.

Abstract: Traditional mechanical punching machines are mainly driven by rotary motors and a complete set of intermediate transformation mechanism is needed, which results in a reduction of the system efficiency. This paper focuses on the tubular linear induction motor (TLIM) with low cost and simple control structure which directly drives the punching machines. In order to provide a theoretical basis for its further control system, the finite element model of this TLIM is established. The starting performances, such as the trust force, phase current, velocity, displacement and the load force, are analyzed by the finite element analysis (FEA). Moreover, the optimization of the starting trust force is investigated.

Abstract: This paper proposes a permanent magnet single-phase linear generator (PMSPLG) with Halbach PM Array applied in wave energy conversion system and illustrates how the parameter changes in the geometry of permanent magnet and slot affect the cogging force of the generator. Moreover, the cogging force analysis method in PMSPLG is improved based on the cogging torque analysis method of permanent magnet synchronous rotation machine. Due to experiment results of prototype concordant with the analysis results of the analytical method and the finite-element method, the proposed model and analytical method are correct and effective.

Abstract: A contactless energy transmission system is essential to supply onboard systems of magnetically levitated vehicles without physical contact to the guide rail. This paper introduces a contactless power supply (CPS) where the primary is integrated into the guide rail of an electromagnetic guiding system (MGS). The secondary is mounted onboard the elevator car. The advantages of this system when compared to existing energy transmission systems are the low requirement of construction space and reduced costs.

Abstract: The stationary discontinuous armatures that are used in permanent magnet linear synchronous motors (PMLSMs) have been proposed as a driving source for transportation systems. However, the stationary discontinuous armature PMLSM contains the end edges which always exist as a result of the discontinuous arrangement of the armature. For this reason, the high alteration of the end edge cogging force produced between the armatures core and the movers permanent magnet when a mover passes the boundary between the armatures installation part and non-installation part has been indicated as a problem. Therefore, we have examined the end edge cogging force by installing the double-auxiliary teeth at the end edge of the armature in order to minimize the end edge cogging force generated when the armature is arranged discontinuously. This paper presents the results of 2-D numerical analysis by FEM of the cogging force exerted by the end edge.

Abstract: The 2D nature of magnetic field in permanent magnet flux-switching machines and the presence of all magnetic field sources [permanent magnets and windings (armature windings and eventually excitation coils)] in the stator, which implies a completely passive moving armature, makes them very good candidates in many different applications. Due to these interesting features, rotating and linear permanent magnet flux switching structures attracted considerable research efforts in the last years. However, to date, the overload capability of this kind of structures has not been investigated in detail. The study presented in this paper will help identify main factors limiting the improvement of overload capability for PM flux switching machines. Solutions to improve this characteristic will also be explored.

Abstract: Linear switch reluctance machine (LSRM) has been an alternative to linear permanent magnet synchronous machine and linear induction machine. However, the nature of reluctance force production, together with the air gap which is always much larger than rotary SRM, result in low propulsion force density in LSRM. This is an inherent demerit of LSRM, limiting its applications where the machine size is strictly set. This paper presents a novel linear switch reluctance machine with segmental stator, which consists of series of ferrite-magnetic segments. The principle of the proposed LSRM featuring high force density has been introduced. A variety of topologies of the proposed machine have been presented including single stator, dual stator and non-stator yoke structure. This paper deals with the comparison of the proposed segmental stator linear switch reluctance machine and traditional teeth type linear reluctance machine in terms of the propulsion force, normal force and force ripple as well as the force density and active pay load ratio. Finite Element Method is implemented to obtain the correlated results. Some conclusions are drawn to verify the analysis above.