Magnetic modelling of continuously variable transformers

Continuously variable signal transformers utilise the variation of the incremental permeability of ferromagnetic or ferrimagnetic materials with an applied DC magnetisation. The hysteresis losses play the dominant role determining the losses of the transformer. The losses mainly depend on the amplitude of the AC excitation and DC magnetisation. The energetic model for ferromagnetic hysteresis is used to calculate major and minor hysteresis loops and approximately determine the losses (Rayleigh law).