Reduction of armature reaction and inductance in the moving coil linear actuator for a high performance drive

Summary form only given. In a moving coil linear actuator, the armature field shifts and distorts the airgap flux density distribution due to the magnet alone by a certain amount, which causes the unbalanced reciprocating force. In this paper, we propose a reduction method for the armature reaction and coil inductance to decrease the unbalanced force and shorten the access time. The proposed model has a shorted ring, a saturated core, differential winding, and a Halbach array. The shorted ring consists of a conductive layer material and aids the coil current in changing state rapidly. Moreover, a magnetically saturated core is used in order to suppress the increase of the moving coil inductance. The MMF of each coil of the differential winding are opposite. The coil inductance of the Halbach array model is much lower because of the magnetic circuit with an air-core. A general model and four types are compared with respect to their topology, size, inductance, force constant, and response time. The comparison of force constant according to coil current is shown.