Due to high power density, saturation is a common phenomenon in linear motors in the field of electromagnetic launch, and saturation affects both motor performance and motor control. As regard to this problem, the traditional magnetic circuit calculation method is no longer applicable. While the finite element method does not help to deeply understand its physical mechanism on the one hand, and is not applicable in the stage of frequent adjustment of the scheme on the other hand. In this paper, a distributed magnetic circuit method for linear motors is proposed, which is based on the magnetic motive force and Ampere circuit rule, and adopts the idea of nodal division and iterative calculation to achieve an accurate calculation of the flux density of each part of the motor. The method can calculate both the no-load saturation characteristics of the motor and the accurate calculation of the motor electromagnetic force in the case of unknown motor parameters. The correctness of this method is verified by comparing simulation and experiment.

high-power linear induction motor， magnetic circuit calculation， flux density distribution， saturation characteristics