Semi-analytical modeling for linear motors with conductive media in high-dynamic applications

Conductive surfaces in linear motors, performing high-dynamic motion, generate significant losses and parasitic forces due to eddy-currents. While FEA models can estimate these effects accurately, their long computing time makes them unfavorable for parametric analysis of the motor. Therefore, a computationally faster and accurate tool using semi-analytical techniques is developed for these linear motors. This tool is applied to a superconducting linear motor where eddy-current losses within the cryostat are critical to the performance. The modeling tool is applied to two benchmark models of such a motor. Using benchmark 1, the developed tool is validated with FEA. The tool shows a major improvement in computation time when compared to FEA, with a relative error in instantaneous loss and force below 3%. For these reasons, the developed tool is suitable for parametric analysis of the motor. In another study, a superconducting motor with essential conductive structures - cryostat wall, radiation shield, and cooling platform - is considered for a parametric analysis. Results show that eddy-current losses increase when using higher number of turns for the superconducting coils on account of larger volume of the conductor and higher armature reaction.