Applied Mechanics and Materials Vols. 416-417

Abstract: A water-cooled, double-sided permanent magnet linear synchronous motor (PMLSM) is studied by electromagnetic and thermal finite-element (FE) analysis method. Based on electromagnetic analysis, the better structure of this double-sided PMLSM can be obtained after thrust optimization by adjusting motor structure parameters. In order to minimize the thrust ripple, it is further optimized by shifting permanent magnets or armature iron cores of two sides for a small distance. With thermal analysis, the temperature distribution and transient temperature variation of this optimal PMLSM are investigated under the continuous operation and the short-time operation.

Abstract: The characteristic of linear induction motor (LIM) is rather different to that of rotary induction motor (RIM). In this paper, the mathematic model of LIM is firstly developed based on the analysis of parameter variations. Then the mechanical and traction characteristic of the LIM and RIM are calculated and compared from different perspectives. Finally, the control law of LIM is deduced for the high performance traction control of linear motor metro vehicles.

Abstract: A novel 2-D permanent magnet array for a planar actuator was proposed, in which the portion between adjacent magnetic poles was divided to four small rectangular solids. Magnetic fields of the permanent magnet array were analyzed systematically by 3D finite element method. The analysis results show that, compared with the well-known Halbach magnet array, the proposed array has higher permanent magnet utilization. Keeping the whole permanent magnet volume constant, the arrays with several improved structures were put forward. The magnetic field analyze results prove that the utilization is best, when the ratio between the height of the magnetic poles magnetized vertically and the height of the portion magnetized horizontally is about 2.

Abstract: The paper explores the use of quadrature axis flux barriers in planar linear synchronous motors. It is shown that the use of the barriers produces a decrease in the flux driven by the armature windings. This leads to a reduction in the tendency for de-magnetisation of the magnets and improved power factor with only a minor reduction in the force. A simple analysis is developed to enable broad assessments of the flux barrier effects and this is validated by the use of 2D finite element analysis in a time stepping routine. The simple analysis is used to consider machines of three different pole pitches with a range of quadrature axis gap dimensions. The braking force produced in short circuit conditions is important in some applications and it is shown that the use of flux barriers gives enhanced forces.

Abstract: In this paper, two novel topological structures of sliding transformer with ferromagnetic core applied in the Contactless Electrical Power Transmission (CEPT) system used for the ropeless elevator driven by moving-coil type Permanent Magnet Synchronous Linear Motor (PMLSM) have been proposed, and the magnetic field distribution is calculated and analyzed by the finite element method (FEM). According to the analysis results of the traditional E-E topology sliding transformer, much higher coupling coefficients of sliding transformers with proposed topologies have been obtained. Then, based on the magnetic distribution and the circuit model of system, the compensation capacitances have been calculated considering supply frequency and load conditions. Finally, the load characteristic of the system with compensation is also obtained by FEM.

Abstract: The permanent magnet linear synchronous motor (PMLSM) has a good application prospect due to many significant advantages such as high speed, high precision, high thrust force density, simple structure, energy saving and reliable operation etc., so the research and development are of great importance. This paper mainly focuses on the key design points of a double-sided water-cooled PMLSM. According to the required thrust force, the design is given out including the basic structure parameters, winding connection methods and water cooling system. Based on the erected finite-element model, the performances such as back-EMF, thrust force, normal force, power factor and efficiency are predicted. By comparing with a single-sided PMLSM with the same specifications, it is proved that this double-sided PMLSM has lower thrust force ripple and higher thrust force density. Moreover, the net normal force of its mover is almost zero. Finally, the predicted back-EMF is verified by measurement.

Abstract: The cogging torque of a novel dual-rotor axial field flux-switching permanent magnet (DRAFFSPM) machine is investigated in this paper. The analytical equation of the DRAFFSPM machine is deduced. Based on 3D finite element method, the influences of the design parameters on the cogging torque are analyzed. The H-shaped stator tooth with slot chamfer is proposed and the slot opening width and chamfer thickness are optimized to reduce the cogging torque. It shows that the cogging torque is the minimum when the stator tooth width and stator magnet width equal to 8^o and 7.5^o mech., respectively. The cogging torque can be reduced by ~64% when the rotor pole width is 1.6 times that of the original design. The cogging torque can be reduced by ~80% when the chamfer is added in the stator slot.

Abstract: There are many slot/pole combinations may be selected for the fractional slot tubular linear surface-mounted motors (TLSPM) used as actuators for high voltage breakers, such as 15/8, 15/4, 15/2, 12/8. Compared with integral slot winding, the fractional slot winding has more advantages. Since the winding arrangement will be changed due to the different slot/pole numbers. The characteristics of the TLSPM with different fractional slot, such as detent force, back EMF, are analyzed and compared in this paper. It is shown that good performance may be achieved by selecting appropriate fractional slot design.

Abstract: A double-sided linear flux-switching permanent magnet machine applied in marine rudder direct drive applications is presented. The starting performances of the machine are calculated by finite element method. The simulation results of the proposed DLFSPM are verified by the experiment. The results have verified that the machine is suitability marine rudder direct drive applications.

Abstract: This paper deals with the manufacturing and the experimental verification of a tubular, linear, permanent magnet (TLPM) motor. A brief re-cap regarding the design and optimization procedures of a high force density, TLPM motor, presented in previous papers is first given. The design includes a novel, thermal management technique that is implemented in order to improve the thermal performance and thus improve the force density performance of the machine. Manufacturing and assembly of tubular motors is traditionally difficult and costly, thus details of the manufacturing and assembly procedures adopted are presented. The TLPM motor is finally assembled on a dedicated aerospace drive rig fed through a matrix converter. Experimental validation is achieved and compared to the modeling results.