Analytical Magnetic Model for Variable-Flux Interior Permanent Magnet Synchronous Motors

In this paper, we present a new semi-analytical magnetic modeling method for a variable-flux interior permanent magnet synchronous motor (IPMSM), which features both permanent magnets and field windings in the rotor. Developed on subdomain framework, we account for all the excitation sources in the machine, the finite permeability of rotor core, and the stator slotting effect in the calculation to obtain key electromagnetic performance metrics, such as air-gap flux density, back-EMF and torque. The calculation is validated with high-fidelity finite-element simulations and experimental results from a prototype motor. The method is shown to achieve good accuracy with rapid calculation, making it suitable for motor design optimization.