3D finite element computation of a linear transverse flux actuator

The principle of operation of a linear permanent magnet transverse flux motor has been described in a previous paper by H. Vande Sande et al. (see Proc. of COMPUMAG, p.54-5, 2001). This actuator is intended to operate in a computer peripheral device which requires a fast and accurate positioning, while the dimensions are strictly limited. Transverse flux machines can achieve such a high force/volume ratio and are therefore suited for this application. As explained in detail below, the particular configuration with two motors facing each other described previously not only makes optimal use of the available volume, but allows also an advantageous combination of the force profiles of the two motors. Due to the complexity of the flux path in the airgaps, a parameterized 3D finite element model has been set up to allow an accurate computation of the force acting on the mover. Particular attention has been paid to end effects. The principle of operation of the machine has been established on the basis of these results and the performances of the actuator have been compared with the specifications. The influence of the number of mover blocks has been studied with a view to the geometrical optimization of the mover.