Parametric transformer

The paraformer is a particular type of transformer. It transfers the power from primary to secondary winding not by mutual inductance coupling but thanks to the variation of a parameter of its magnetic circuit.

Assuming inductor's law

$v(t)=L{\frac {di(t)}{dt}}$

it is possible to obtain a voltage at the secondary winding terminals also thank to a variation of the inductance, so that

$v(t)=I{\frac {dl(t)}{dt}}$

This can be accomplished by for example modulating the saturation of the core by means of an applied variable magnetic field. It works even if primary and secondary windings magnetic coupling is zero (when fluxes are mutually Orthogonal).