Bidirectional Current-Voltage Converter Based on Coil-Wound, Intermagnetically Biased, Heterostructured Magnetoelectric Ring

We report theoretically and experimentally a passive bidirectional current-voltage (I-V) converter, capable of converting input currents into output voltages, and conversely, input voltages into output currents, based on a multiphase heterostructured magnetoelectric (ME) ring. The ME ring has a coil-wound, intermagnetically biased magnetostrictive-piezoelectric (MS-PE) heterostructure, in which an axially polarized PZT PE ceramic ring is bonded between two circumferentially magnetized, intermagnetically biased Terfenol-D short-fiber/NdFeB magnet/epoxy three-phase MS composite rings. In I-V conversion, a current applied to the coil induces a vortex magnetic field to the ME ring, resulting in an open-circuit voltage from the ME ring because of the direct ME effect. In voltage-current (V-I) conversion, a voltage applied to the ME ring produces a circumferential magnetic induction due to the converse ME effect, leading to a short-circuit current from the coil. The converter exhibits simultaneously large I-V and V-I conversion factors of ∼ 0.3 V/A and ∼ 0.2 mA/V in a broad non-resonance frequency range up to 80 kHz as well as enhanced conversion factors of ∼ 7 and ∼ 25 times at the resonance frequency of 122 kHz, respectively.