A GaN-based wireless power and information transmission method using Dual-frequency Programmed Harmonic Modulation

Information transmission is often required in power transfer to implement control. In this paper, a Dual-Frequency Programmed Harmonic Modulation (DFPHM) method is proposed to transfer two frequencies carrying power and information with the single converter via a common inductive coil. The proposed method reduces the number of injection tightly coupled transformers used to transmit information, thereby simplifying the system structure and improving reliability. The performances of power and information transmission, and the method of information modulation and demodulation, as well as the principles of the control, are analyzed in detail. Then a simulation model is set up to verify the feasibility of the method. In addition, an experiment platform is established to verify that the single converter can transfer the power and information simultaneously via a common inductive coil without using tightly coupled transformers.Web of Science8498564984

Communication system for a tooth-mounted RF sensor used for continuous monitoring of nutrient intake

In this Thesis, the communication system of a wearable device that monitors the user’s diet is studied. Based in a novel RF metamaterial-based mouth sensor, different decisions have to be made concerning the system’s technologies, such as the power source options for the device, the wireless technology used for communications and the method to obtain data from the sensor. These issues, along with other safety rules and regulations, are reviewed, as the first stage of development of the Food-Intake Monitoring projectOutgoin

Design and control of a bidirectional wireless charging system using GaN devices

Most of the existing wireless power transfer system works in unidirectional with one-direction control signals. This paper presents a bidirectional wireless charging system with duplex communication method, which is not only able to achieve the two-way wireless power transmission, but also transfer control signals bi-directionally. The power circuit operation mode is actively controlled by using the wireless transceiver module which can duplex communication to deliver measured signals remotely. The operational principle is analytically studied in details and is verified by simulation. Finally, a prototype of the bidirectional charging system using GaN devices has been successfully designed and tested. In addition, the measured feedback signals are effectively transmitted to validate the control algorithm

Structural behaviour of beam with HDPE plastic balls subjected to flexure load

This paper presents the structural behavior of reinforced concrete beam embedded with high density polyethylene balls (HDPE) subjected to flexural load. The HDPE balls with 180 mm diameter were embedded to create the spherical voids in the beam which lead to reduction in its self-weight. Two beam specimens with HDPE balls (RC-HDPE) and one solid beam (RC-S) with dimension 250 mm x 300 mm x 1100 mm were cast and tested until failure. The results are analysed in the context of its ultimate load, load-deflection profile, and crack pattern and failure mode. It was found that the ultimate load of RC-HDPE was reduced by 32% compared to RC-S beam while the maximum deflection at its mid span was increased by 4%. However, RC-HDPE is noticed to be more ductile compared to RC-S beam. Both types of beams experienced flexure cracks and diagonal tension cracks before failur