Traveling wave piezoelectric transformers are a new type of multi-electrodes piezoelectric transformer allowing to obtain a multiphase system of voltages at the output. The behavior of multi-electrodes piezoelectric transformers is well characterized by an admittance matrix (Y) representing all the couplings between electrodes. The Y parameters can be determined by analytical modelling or as presented in this paper by experimental measurements. In this paper we focus on a cylinder-type multi-electrodes piezoelectric transformer on which we measure the Y parameters with a vector network analyzer. By extrapolation of Laplace expression of the admittances, we represent the Y-parameters as equivalent RLC circuits in order to have a complete circuit model available for simulation with classic electrical simulation software. The results of the simulation are compared to experimental results to validate the modelling approach.
This paper proposes a compact electromechanical modeling of multi-electrode piezoelectric transformer. This modeling can be applied to the study of standing or traveling flexural wave in piezoelectric systems and especially for ring type piezoelectric transformers. This modelling is based on the Euler-Bernoulli beam theory and from this theory and piezoelectric equations, transfer matrixes linking stresses, velocities and voltages for a beam are determined. In piezoelectric systems with no mechanical boundary in the propagation direction of the wave, for example a ring, an admittance matrix is obtained from the modeling linking all the currents and voltages. This modelling allows moreover the representation and electrical simulation of a piezoelectric element subjected to a traveling wave.
CMOS technology allows a femto Joule energy dissipation per logic operation, if operated at optimal frequency and voltage. However, this value remains orders of magnitude above the theoretical limit predicted by Lan-dauer. In this work, we present a new paradigm for low power computation, based on variable capacitors. Such components can be implemented with existing MEMS technologies. We show how a smooth capacitance modu-lation allows an energy-efficient transfer of information through the circuit. By removing electrical contacts, our method limits the current leakages and the associated energy loss. Therefore, capacitive logic must be able to achieve extremely low power dissipation when driven adiabatically. Contactless capacitive logic also promises a better reliability than systems based on MEMS nanorelays.
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