Microfabricated electrodynamic transformers for electromechanical power conversion

Abstract

This paper presents a compact power electronic device, called an ‘electrodynamic transformer (ET)’, that transfers electrical power between isolated circuits through electrodynamically coupled vibrations of a mechanical beam structure. Background motivating factors are discussed, and an equivalent circuit model of the ET is presented. A microscale (10 mm3) ET is designed, fabricated and characterized, achieving ∼40% maximum efficiency. Taking advantage of the unique circuit topology of the ET equivalent circuit model, a dc/ac power inverter is then implemented with only two external components, a MOSFET and a capacitor.

Hybrid Piezo/Magnetic Electromechanical Transformer

“…In contrast to PTs, our group previously demonstrated the feasibility of an electrodynamic transformer (ET) operating at a very low resonance frequency of only 22 Hz [20]. Like a PT, an ET leverages the mechanical domain to exchange electrical power between input and output ports, but uses electrodynamic transduction (interaction between a permanent magnet and coil) on both ports, in contrast to a PT, which uses piezoelectric transduction [20][21][22]. Electrodynamic transducers generally exhibit much lower electrical impedance (correspondingly lower voltages and larger currents) in comparison to piezoelectric transducers.…”

Thin-film piezoelectric transformers operating in harmonics of out-of-plane flexure modes

“…Electromechanical resonators and transformers feature a number of advantages over their traditional magnetic counterparts: large energy/power densities, absence of electromagnetic noise, large inductance densities, and frequency selectivity with narrow bandwidth [5][6][7][8]. In the 10's-100's MHz range, magnetic-materials based inductors with quality factors, Q, exceeding 10 have been limited [9].…”