Comparison of Force Density of Various Superconducting Linear Motor Types Considering Numerically Evaluated AC Losses

This paper presents a comparison of the force density of four types of superconducting linear motors, taking into account the ac losses. The losses are evaluated by finite-element models, in which several methods to reduce model complexity are combined to achieve a low computation time. A parametric search is performed to determine the maximum achievable force density of all motor types, in which the operating temperature, geometric parameters, and peak current through the superconducting coils are varied. Results show the optimum number of turns for each motor type and that a force density around 2500 N/dm 3 can be achieved by all four motor types at 20 K.