Abstract
Surface Motor (SFM) was proposed to realize bi-directional direct drive with single body. Static thrust force obtained in the prime design, however, is not surfficient for practical application. Method of numerical analysis for designing the actuator is needed for the improvement and further optimization. Finite element analysis is commonly used for these purposes. Two-dimensional analysis is not applicable for SFM, because the planer distribution of the permanent magnet and the locus of the mover inductor both affect the thrust characteristics. Three-dimensional analysis needs much calculation time and data storage capacity, and is not suitable for iterative calculation in the optimizing process. The intermediate scheme of these analysis is consequently needed.
This paper first describes the basic structure of SFM, and then the limitation of two-dimensional analysis. Approximated three-dimensional analysis is proposed on the basis of these studies. Three-dimensional structure of the inductor, surface distribution of the permanent magnet and the interaction between the inductors and the stator are taken into account in the approximation, and the results of the two-dimensional analysin are corrected. Thrust characteristics calculated by the method are compared with the experimental results, and the accuracy and the feasibility of the scheme are proved.
