Magnetic Material Modeling

This chapter introduces some shape preserving interpolation (including extrapolation) schemes. It shows that the derivative of the linear interpolant discontinues at each sampling point, which may cause the Newton‐Raphson iteration in finite element analysis (FEA) not to converge to a smaller error. The quadratic spline interpolation is also based on the pre‐selected discrete derivative set. Anisotropic behavior is often encountered not only in the grain oriented but also in the laminated grain non‐oriented magnetic cores in electromagnetic devices. The chapter presents case study of a 400 W 4‐pole synchronous reluctance motor with axially laminated anisotropic rotors. Permanent magnet (PM) machines are usually designed with reasonable demagnetization in normal working conditions. In some occasional cases, a PM motor may operate at an overloaded torque. The chapter presents an algorithm to construct demagnetization curves for magnetization.