Frequency-Domain Analysis and Design of Thomson-Coil Actuators

Thomson coil actuators consist of an electric coil repelling a metallic disk. They are considered the fastest electromagnetic actuators for short travels and for this reason are favored for DC circuit breakers. Although the basic physics are understood, the actuator’s few components are very interdependent, making for a difficult analysis. Actuator design so far has thus been limited to trial and error based on finite-element models. In this paper, a novel approach is presented based on the electromagnetic frequency response of the actuator. This method is shown to be an intriguing analysis tool and various actuator design directions are presented. Experimental results provide a confirmation of the analysis.