Electromagnetic force characteristics in long-stator PM linear launcher with non-ideal mechanical air gap condition

The designs of long-stator permanent magnet (PM) linear launcher are widely adopted modular segments to simplify system and reduce energy losses. The assembled segments structure causes non-ideal mechanical air gap condition inevitably, and it brings significant effects on electromagnetic performance. Hence, this paper investigates electromagnetic force characteristics in long-stator PM linear motor with non-ideal mechanical air gap condition. First, the non-ideal mechanical air gap conditions are categorized, and then corresponding calculated models by finite element method are proposed. The influence of non-ideal air gap conditions on electromagnetic thrust, detent force and normal force characteristics are analyzed respectively. These studies can provide references to operational analysis and assembly process of electromagnetic launcher based on long-stator PM linear motor.