Performance Enhancement of an Ultrasonic Power Transfer System Through a Tightly Coupled Solid Media Using a KLM Model

Abstract

Contactless ultrasonic power transmission (UPT) through a metal barrier has become an exciting field of research, as metal barriers prevent the use of electromagnetic wireless power transfer due to Faraday shielding effects. In this paper, we demonstrate power transfer through a metal wall with the use of ultrasonic waves generated from a piezoelectric transducer. Accurate characterization and modeling of the transducer and investigation of the influence of the acoustic properties of the transmitting medium are instrumental for the performance prediction and optimal design of an ultrasonic power link. In this work, we applied the KLM model for the emitting and receiving transducers, with respect to the transmitting medium and model for both the emission and reception function. A practical UPT system was built by mechanically coupling and co-axially aligning two composite transducers on opposite sides of a transmitting medium wall. The optimal transmission performance of the ultrasonic power link through thickness-stretch vibrations of the wall together with two piezoelectric transducers working in TE mode was determined. Eventually, the operating frequency and ohmic loading condition for maximum power transmission were obtained for two different media, aluminium and polyoxymethylene (POM), with contrasting specific acoustic impedances. The results showed that the measured optimal electric loads and operating frequency for maximum power transfer agreed well with the theoretical predictions.

Development of a Pressure Control System According to Paste Rheology for Ultrasound Processing in Industrial Olive Oil Extraction

“…To better understand this behavior, let us consider a paste flow rate of 3000 kg/h. When batch OP1 was processed using the IUP-SE, the operating pressure reached about 2.64 ± 0.18 bar, and the sonotrode provided a power intensity of about 118 W/ cm 2 (sonotrode surface area of 41 cm 2 ) and an average total power of about 4838 W; when processing batch OP2 in the IUP-SE, the operating pressure reached about 2.96 ± 0.18 bar and the sonotrode provided a power intensity of about 130 W/cm 2 (sonotrode surface area of 41 cm 2 ) and an average total power of about 5330 W. When batch OP3 was processed in the IUP-SE, the operating pressure reached about 3.21 ± 0.20 bar and the sonotrode provided a power intensity of about 138 W/cm 2 (sonotrode surface area of 41 cm 2 ) and thus an average total power of about 5658 W. Discontinuity in olive paste flow behavior within the cell decreases ultrasound transmission, alters the power and energy transferred to the matrix, and generates ultrasonic reactor malfunctions or blockages (Astráin-Redín et al, 2020;Kar & Wallrabe, 2020). These results highlight that ultrasound treatment of non-Newtonian olive pastes can induce variations in the operating parameters defining the effect of the acoustic wave; maintenance of the pressure value during ultrasonic treatment is therefore essential for the functioning of these systems.…”

Recent Development and Perspectives of Optimization Design Methods for Piezoelectric Ultrasonic Transducers

“…Compared with PUTs made with other materials, the fabricated PUT had high electromechanical coupling coefficients and low insertion loss. Additionally, Kar et al [ 27 ] constructed a contactless ultrasonic power transmission system by using the KLM model, as shown in Figure 3 B. This system had metal shielding effect, which could effectively reduce the energy transmission loss.…”

“… ( A ) Electrical impedance amplitude and phase variation with frequency, pulse-echo waveform, and spectrum of needle piezoelectric ultrasonic transducer (reproduced from [ 26 ]); ( B ) ultrasonic power transfer experimental setup diagram and KLM equivalent circuit diagram (reproduced from [ 26 ]); ( C ) needle-type piezoelectric ultrasonic transducer, 4 um tungsten wire imaging schematic, and acoustic tweezers manipulating particles to form USC patterns (reproduced from [ 27 ]); ( D ) schematic diagram of a dual-frequency confocal transducer (reproduced from [ 28 ]); ( E ) 1-3 piezoelectric composite ultrasound transducer structure, emission voltage response, and simulated impedance (reproduced from [ 29 ]); ( F ) BDF-PT ultrasonic transducer (reproduced from [ 30 ]). …”

Wireless Passive Sensor Technology through Electrically Conductive Media over an Acoustic Channel

“…In contrast to electromagnetic or inductive transmission, acoustic waves propagate well through liquid or solid media, independent from their electrical conductivity. Acoustic wave propagation is exploited in numerous fields, such as diagnostic and therapeutic ultrasound for medical applications [ 5 ], non-destructive testing [ 6 ], indoor localization [ 7 ], and electrical energy transfer [ 8 ]. Ultrasonic waves in the low kHz range are utilized when mechanical or electrical energy is transferred with high power levels or over long distances, as in ultrasonic cleaning baths or underwater sonar.…”