Nonlinear Modeling of Electromagnetic Forces for the Planar-Switched Reluctance Motor

This paper proposes novel nonlinear electromagnetic force models of a planar switched reluctance motor (PSRM) for accurate optimization design and precise motion of PSRMs. For the mover with exciting current and the adjacent stator blocks, the flux distribution is gained by the finite-element method, the air-gap permeance between the mover tooth and the adjacent stator blocks is deduced using the flux tube method, the total permeance of the mover and the stator blocks is formulated utilizing the magnetic equivalent circuit method, and the magnetic field energy and the coenergy are derived with the obtained total permeance. In addition, the nonlinear electromagnetic forces, including thrust force and normal force, are modeled based on the magnetic field energy and the coenergy. The simulation and experiment are carried out to acquire electromagnetic forces. The results demonstrate that the average relative errors of the simulated and measured electromagnetic forces compared with the theoretical electromagnetic forces are <10%, and the accuracy and effectiveness of the proposed modeling are verified.