Advanced Modeling of a 12/10 Variable Flux Reluctance Machine Using Winding and Air-Gap Permeance Functions Considering Saturation and Skew Effects

This article proposes an advanced analytical model for a 12-slot, 10-pole variable flux reluctance machine (VFRM) based on field and armature winding functions, as well as stator and rotor permeances. The model calculates the magnetomotive force (MMF) drop factor by solving a simple magnetic circuit involving discrete permeances to account for the nonlinear magnetic behavior of the core material. The discrete air-gap permeance per stator tooth is determined by integrating the overall air-gap magnetic permeance function for each tooth. In addition, the model incorporates the effect of rotor skewing on the back electromotive force (back EMF) and electromagnetic torque output, which is critical for minimizing torque ripple and cogging torque in motor design. Key performance parameters, such as torque, torque ripple, cogging torque, and back EMF, are derived using the proposed model. The validity of the analytical model is confirmed through finite element analysis (FEA) and experimental measurements of back EMF and torque, demonstrating its accuracy and effectiveness in predicting motor performance.