Analysis of a Dual-Transduction Receiver for Electrodynamic Wireless Power Transfer

In this article, we present the characterization and an experimentally validated electromechanical model of a dual-transduction receiver for electrodynamic wireless power transfer (EWPT) system. This dual-transduction EWPT receiver contains two unimorph-type, series-connected piezoelectric transducers and an electrodynamic transducer within a compact footprint and low-profile design. The receiver makes simultaneous use of both piezoelectric and electrodynamic transducers to generate electrical power while operating at its torsion mode mechanical resonance at ∼744 Hz. The electromechanical system behavior and output performance under low-frequency, magnetic near-fields are analyzed by establishing an equivalent lumped-element equivalent electrical circuit model. A prototype device is fabricated, assembled, characterized, and the experimental results are compared with the model predictions under various excitation and loading conditions. A maximum of 49 μW average power is generated by the prototype under 120 μT
_rms
, which corresponds to 0.54 mW·cm
^–3
power density and 37 mW·cm
^–3
·mT
^–2
normalized power density. This chip-sized (0.09 cm
³
) design offers an innovative and volume-efficient architecture for application in wirelessly charging wearable and implantable medical devices.