Low Cost Flux Switching Linear Hybrid Actuator

Abstract

International audienceIt's now possible to better satisfy the need for direct linear actuators. In particular, the household applications represent an expanding market. The principal constraints are the cost and the noise. We propose, in this paper, a new electromagnetic structure in which the rail is passive (without permanent magnets and without conductors) and where the mobile part (primary) has ferromagnetic pieces, permanent magnets and coils with simple forms very easy to build. The presence of permanent magnets permits obtaining good performances with high efficiency even for smaller sizes. Moreover the performances are not very sensitive to the airgap length. In comprison with induction and switched reluctance motors. Yhis last characteristic is important in order to have easy guiding. The present structure I cellular and works on the principle of permanent magnet flux switching during movment. We describe its principle, and we perform an analysis of the significant dimensional parametric influence. The electromagnetic phenomena is basically 3D, but to simplify the understanding, the analysis is based initially on an analytic modelling in linear mode and then on a numerical computation by 2D finite element method. We then show an experimental structure for which we compare the theoretical results and the measurements of static effort. We also provide a synthesis of the experimental results obtained with many types of permanent magnets and with several numbers of cells. Finally, we show the results of the dynamic operation when the actuator is supplied by an electronic inverter and self-driving system with indirect position sensors