Several well-known analytical techniques exist for the force profile analysis of permanent-magnet linear synchronous motors. These techniques, however, make significant simplifications in order to obtain the magnetic field distribution in the air gap. From the field distribution, the force profile can be found. These widely used techniques provide a reasonable approximation for force profile analysis, but fail to give really accurate results in the sense of the exact shape of the force profile caused by effects that due to simplification are not fully included. To obtain the exact shape for the force profile in these cases, the computationally expensive finite-element method (FEM) is often applied. In this paper, an elegant semianalytical approach is presented to acquire the force profile. First, the magnetic field distribution in the air gap is determined by means of Schwarz-Christoffel (SC) mapping. The SC mapping allows a slotted structure of the machine to be mapped to a geometrically simpler domain for which analytic solutions are available. Subsequently, the field solution in the slotted structure can be determined by applying the mapping function to the field distribution in the simplified domain. From the resulting field distribution, the force profile is calculated by means of the Maxwell stress tensor. The results are compared with those from the commonly used equivalent magnetic circuit modeling and 2-D FEM software to demonstrate the accuracy which can be reached by application of the SC method.

Abstract-This paper discusses the optimal design of a pot core rotating transformer to replace wires and slip rings in mechatronic systems by means of contactless energy transfer. Analytic models of the transformer are derived in the electromagnetic and thermal discipline. The models are compared with both 2D/3D FEM simulations and measurements. The analytical models are combined and used in a multi-objective sequential quadratic programming algorithm to find the minimal Pareto front in terms of volume and power loss for comparison of the adjacent and coaxial winding topologies. Finally, the optimization algorithm is used for the design of two prototype rotating transformers for a power transfer of 1kW peak, rotating at 4000 rpm. The prototypes are manufactured and tested in an experimental setup.

Φ Abstract -A novel three-phase double sided flux switching linear motor topology with a stator-to-mover teeth ratio of 19/24 is presented. Finite element analysis of the electromagnetical performance of the initial design is conducted and shows that the topology suffers from an unbalanced EMF in terms of amplitude and phase shift between the three phases. On the other hand a low detent force is observed. By adding end-teeth to the structure, a balanced EMF is obtained, but the detent force also increases. A geometrical optimization is conducted on the end-tooth shape and stator tooth width to reduce the detent force while maintaining a balanced sinusoidal EMF. For the optimization a faster hybrid modeling tool is used. The hybrid model is based on the magnetic equivalent circuit method that employs the boundary element method to accurately determine the air gap permeances of the magnetic equivalent circuit.Index Terms-Flux switching motor, linear motor, magnetic equivalent circuit method, boundary element method.

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