An Ultrasonic Through-Metal-Wall Power Transfer System with Regulated DC Output

Abstract

Featured Application: Wirelessly powering sensors and circuits enclosed in hermetic metal containers.Abstract: This paper presents a novel and efficient system capable of transmitting medium-power electric energy through a solid metal wall and generating a regulated direct current (DC) output. The electric power is transmitted using radio frequency (RF) ultrasound without physical penetration. An RF alternating current to direct current converter with input impedance matching is used to convert the transmitted RF signal to a DC output, which is directly suitable as a power supply for electronic devices. The system is constructed from commercial off-the-shelf components, and a computer-controlled measurement method is designed to test the effectiveness of the full system. The measurement results show that the system is able to transfer power through a 40-mm-thick stainless steel plate and generate 5-V, 15.7-W regulated DC output power with an overall power transfer efficiency of 27.7%. In addition, the effectiveness of the system is successfully demonstrated by powering ARM ® evaluation boards with liquid-crystal display panels. A discussion of potential enhancements that could be made to improve the transfer capability and efficiency of the system is also presented. This system could be applied to improve safety and preserve structural integrity in many industrial and military applications, such as submarines, space crafts, planes, nuclear storage facilities, etc.

An Optimal Design Method for Improving the Efficiency of Ultrasonic Wireless Power Transmission during Communication

“…Figure 3 b,c show the matching network that meets the SCIM conditions of the channel. Refer to the paper [ 19 ] for the specific design process. The nominal values of the capacitors and inductors used are marked in Figure 3 c. It can be seen that the nominal values of the components used in the actual circuit do not agree with Figure 3 b.…”

“…However, there are many challenges in the development of this technology. Such as, how to improve the energy transmission efficiency [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ], how to increase the communication rate [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ] and the integration and application of the system [ 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ].…”

“…The channel DC energy transfer efficiency (the ratio of the channel output DC power to the channel input power) is 19%. Yang [ 19 ] used a radio frequency AC-DC converter based on resonant rectifier bridge technology to convert the high-frequency AC of the ultrasonic output into a DC output, which can be directly used as the power supply of electronic equipment. The output power of the DC terminal is 15.7 W, and the channel DC energy transfer efficiency is 27.7%.…”

Analytical optimization of piezoelectric acoustic power transfer systems

“…The maximum achievable efficiency ( ) h f opt is widely used in the APT literature [4,5,28,36] and will be exploited hereafter to compare the various APT configurations on an equal footing, each at its maximum achievable efficiency. However, η does not quantify how much power can be transmitted for a given applied voltage on the emitter (U 1 ).…”

“…Lawry et al [4] have proposed a way to quickly determine the optimal receiver load maximizing the efficiency in order to ease the evaluation of APT performances in simulations and in measurements. Yang et al [5] have developed a highly-efficient AC/DC converter for APT, delivering up to 15.7 W at 5 V-DC. Other teams studied structures different than flat metallic walls, such as pipes, and transmitted power through their thickness [6], or along their length with up to 4 mW transmitted over a distance of 1 m, but with a very low efficiency of 0.1% [7,8].…”