Simulating Ultrasound Piezoelectric Power Transfer in the Near Field and Experimental Validations

2021 ◽  
Vol 05 ◽  
Author(s):  
Ammar Mohammed ◽  
Changki Mo ◽  
John Miller ◽  
David Lowry ◽  
Jassim Alhamid

Background: Acoustic power transfer is a method for wireless energy transfer to implanted medical devices that permits a greater range of separation between transmitter and receiver than is possible with inductive power transfer. In some cases, short-distance ultrasonic power transfer may be employed; consequently, their operation may be complicated by the near-field aspects of piezoelectric acoustic energy transfer. Methods: A piezoelectric energy transfer system consisting of two lead zirconate titanate (PZT) transducers was analyzed in this work using a combination of experimental measurements and computer simulations. Results: Simulations using the COMSOL Software package showed good agreement with a measured output voltage as a function of the distance between and alignment of the transmitter and receiver with water as a medium. We also simulated how operating frequency affects power transfer efficiency at various distances between the transmitter and receiver and found reasonable agreement with experiments. We report model predictions for power transfer efficiency as a function of the thickness and diameter of the transmitter and receiver. Conclusion: The results show that with proper choice of parameters, piezoelectric systems can provide high power transfer efficiency in the near-field region.

2021 ◽  
Vol 2015 (1) ◽  
pp. 012170
Author(s):  
E Zanganeh ◽  
M Song ◽  
M Korobkov ◽  
A Evlyukhin ◽  
A Miroshnichenko ◽  
...  

Abstract The main challenge in near-field wireless power transfer systems is the increase of power transfer efficiency. It can be achieved by reducing ohmic or radiation losses of the resonators included in the system. In this paper, we propose and investigate numerically a non-radiating near-field wireless power transfer system based on transmitter and receiver implemented as dielectric disk resonators. The transmitter and receiver geometrical parameters are numerically optimized to operate at the frequency of non-radiating state of high refractive index dielectric resonators instead of magnetic dipole mode. Under the non-radiating state, we determine the frequency with almost zero radiation to the far-field. We numerically study the wireless power transfer efficiency as a function of operation distance between the transmitter and receiver and demonstrate that the higher efficiency compared to magnetic dipole mode can be achieved at non-radiating state for a fixed distance due to suppression of the radiation loss.


2016 ◽  
Vol 2016 ◽  
pp. 1-11
Author(s):  
Hesheng Cheng ◽  
Huakun Zhang

A metamaterial-inspired efficient electrically small antenna is proposed, firstly. And then several improving power transfer efficiency (PTE) methods for wireless power transfer (WPT) systems composed of the proposed antenna in the radiating near-field region are investigated. Method one is using a proposed antenna as a power retriever. This WPT system consisted of three proposed antennas: a transmitter, a receiver, and a retriever. The system is fed by only one power source. At a fixed distance from receiver to transmitter, the distance between the transmitter and the retriever is turned to maximize power transfer from the transmitter to the receiver. Method two is using two proposed antennas as transmitters and one antenna as receiver. The receiver is placed between the two transmitters. In this system, two power sources are used to feed the two transmitters, respectively. By adjusting the phase difference between the two feeding sources, the maximum PTE can be obtained at the optimal phase difference. Using the same configuration as method two, method three, where the maximum PTE can be increased by regulating the voltage (or power) ratio of the two feeding sources, is proposed. In addition, we combine the proposed methods to construct another two schemes, which improve the PTE at different extent than classical WPT system.


Ceramist ◽  
2021 ◽  
Vol 24 (3) ◽  
pp. 314-326
Author(s):  
Sunghoon Hur ◽  
Hyun Soo Kim ◽  
Hyun-Cheol Song

Wireless energy transfer (WET) is the transmission of electric power without any physical connections such as wires. Currently, inductive coupling mediated by electromagnetic (EM) waves is the most common method of WET and is widely used to charge portable devices such as smartphones, Bluetooth earphones, electric shavers, and visual prostheses. However, its application is still limited due to a number of issues including low efficiency, short charging distance, heating problem, and limited choice of transmission medium. Due to these issues, EM-based WET cannot be applied to implantable medical devices, marine cable operation sensors, and electronic devices with electromagnetic interference shielding. Recently, as an alternative to EM-based WET, acoustic energy transfer mediated by sound waves becomes more attractive. Ultrasound offers advantages for transmission in dense media such as liquids or solids and is regardless of electromagnetic shielding. In this review, we investigate recent progress in acoustic power transfer technology in terms of acoustic energy conversion mechanism and provide the future research direction of acoustic power transfer technology.


Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1417
Author(s):  
Jung-Hoon Cho ◽  
Byoung-Hee Lee ◽  
Young-Joon Kim

Electronic devices usually operate in a variable loading condition and the power transfer efficiency of the accompanying wireless power transfer (WPT) method should be optimizable to a variable load. In this paper, a reconfigurable WPT technique is introduced to maximize power transfer efficiency in a weakly coupled, variable load wireless power transfer application. A series-series two-coil wireless power network with resonators at a frequency of 150 kHz is presented and, under a variable loading condition, a shunt capacitor element is added to compensate for a maximum efficiency state. The series capacitance element of the secondary resonator is tuned to form a resonance at 150 kHz for maximum power transfer. All the capacitive elements for the secondary resonators are equipped with reconfigurability. Regardless of the load resistance, this proposed approach is able to achieve maximum efficiency with constant power delivery and the power present at the load is only dependent on the input voltage at a fixed operating frequency. A comprehensive circuit model, calculation and experiment is presented to show that optimized power transfer efficiency can be met. A 50 W WPT demonstration is established to verify the effectiveness of this proposed approach.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kazunori Takahashi

AbstractDevelopment of a magnetic nozzle radiofrequency (rf) plasma thruster has been one of challenging topics in space electric propulsion technologies. The thruster typically consists of an rf plasma source and a magnetic nozzle, where the plasma produced inside the source is transported along the magnetic field and expands in the magnetic nozzle. An imparted thrust is significantly affected by the rf power coupling for the plasma production, the plasma transport, the plasma loss to the wall, and the plasma acceleration process in the magnetic nozzle. The rf power transfer efficiency and the imparted thrust are assessed for two types of rf antennas exciting azimuthal mode number of $$m=+1$$ m = + 1 and $$m=0$$ m = 0 , where propellant argon gas is introduced from the upstream of the thruster source tube. The rf power transfer efficiency and the density measured at the radial center for the $$m=+1$$ m = + 1 mode antenna are higher than those for the $$m=0$$ m = 0 mode antenna, while a larger thrust is obtained for the $$m=0$$ m = 0 mode antenna. Two-dimensional plume characterization suggests that the lowered performance for the $$m=+1$$ m = + 1 mode case is due to the plasma production at the radial center, where contribution on a thrust exerted to the magnetic nozzle is weak due to the absence of the radial magnetic field. Subsequently, the configuration is modified so as to introduce the propellant gas near the thruster exit for the $$m=0$$ m = 0 mode configuration and the thruster efficiency approaching twenty percent is successfully obtained, being highest to date in the kW-class magnetic nozzle rf plasma thrusters.


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