Controlling voltage step-up ratio of Rosen-type transformer based on magnetoelectric coupling

We proposed a magnetoelectric (ME) composite transformer by bonding a Rosen-type transformer and a Terfenol-D plate, whose voltage step-up ratio could be controlled by an applied magnetic field. When applying a sine signal on the input port of the transformer, an amplifying signal was produced at the output port because of the amplifying effect. Meanwhile, a magnetization was induced in the magnetostrictive part due to the converse ME coupling, and then a voltage at the output port due to the direct ME effect. Superimposition of the ME signal on the amplifying signal resulted that the voltage step-up ratio of the composite transformer could be controlled by the applied magnetic field. In addition, electric-field-induced magnetization in Terfenol-D is very strong, which was dominated by the stress in the composite transformer.