Design and Implementation of a Wireless Charging-Based Cardiac Monitoring System Focused on Temperature Reduction and Robust Power Transfer Efficiency

Wireless power transfer systems are increasingly used as a means of charging implantable medical devices. However, the heat or thermal radiation from the wireless power transfer system can be harmful to biological tissue. In this research, we designed and implemented a wireless power transfer system-based implantable medical device with low thermal radiation, achieving 44.5% coil-to-coil efficiency. To suppress thermal radiation from the transmitting coil during charging, we minimized the ESR value of the transmitting coil. To increase power transfer efficiency, a ferrite film was applied on the receiving part. Based on analyses, we fabricated a cardiac monitoring system with dimensions of 17 x 24 x 8 mm(3) and implanted it in a rat. We confirmed that the temperature of the wireless charging device increased by only 2 degrees C during the 70 min charging, which makes it safe enough to use as an implantable medical device charging system.11Ysciescopu

Micro air vehicles energy transportation for a wireless power transfer system

The aim of this work is to demonstrate the feasibility use of an Micro air vehicles (MAV) in order to power wirelessly an electric system, for example, a sensor network, using low-cost and open-source elements. To achieve this objective, an inductive system has been modelled and validated to power wirelessly a sensor node using a Crazyflie 2.0 as MAV. The design of the inductive system must be small and light enough to fulfil the requirements of the Crazyflie. An inductive model based on two resonant coils is presented. Several coils are defined to be tested using the most suitable resonant configuration. Measurements are performed to validate the model and to select the most suitable coil. While attempting to minimize the weight at transmitter’s side, on the receiver side it is intended to efficiently acquire and manage the power obtained from the transmitter. In order to prove its feasibility, a temperature sensor node is used as demonstrator. The experiment results show successfully energy transportation by MAV, and wireless power transfer for the resonant configuration, being able to completely charge the node battery and to power the temperature sensor.Peer ReviewedPostprint (published version

Wireless Power Transfer

Wireless power transfer techniques have been gaining researchers' and industry attention due to the increasing number of battery-powered devices, such as mobile computers, mobile phones, smart devices, intelligent sensors, mainly as a way to replace the standard cable charging, but also for powering battery-less equipment. The storage capacity of batteries is an extremely important element of how a device can be used. If we talk about battery-powered electronic equipment, the autonomy is one factor that may be essential in choosing a device or another, making the solution of remote powering very attractive. A distinction has to be made between the two forms of wireless power transmission, as seen in terms of how the transmitted energy is used at the receiving point: - Transmission of information or data, when it is essential for an amount of energy to reach the receiver to restore the transmitted information; - Transmission of electric energy in the form of electromagnetic field, when the energy transfer efficiency is essential, the power being used to energize the receiving equipment. The second form of energy transfer is the subject of this book

Control of wireless power transfer system for dynamic charging of electric vehicles

L'abstract è presente nell'allegato / the abstract is in the attachmen

Adaptive Maximum Power Transfer for Movable device in Wireless Power Transfer system

More and more applications are adopting the charging topology of wireless power transmission. However, most wireless charging systems can not charge mobile devices which are moving in position while charging. Currently, many commercialized wireless charging systems adopt an inductive coupling method, which has very short charging distances. In addition, the frequency of the two coupled coils that produce maximum power transfer keeps varying, depending on the coupling coefficient that relies on the separation between coils, and this tendency becomes more severe when the coupling is strengthened at a close charging distance by the phenomenon called frequency splitting. Therefore, the existing wireless power transmission system using a fixed operating frequency can not optimize power transmission for a fluctuating charging environment as the coupling between coils changes, and charging efficiency is greatly reduced by frequency splitting when charging at a very short distance. To solve this problem, we proposed the method of estimating the RX side power and mutual inductance using the information from the TX side such as input impedance rather than using a direct communication link which adds more cost and complexity. Also, we derived a mathematical model for the above estimation method. To prove this mathematical model, the proposed wireless power transmission system was implemented in a SIMULINK environment, and the system model was validated through simulation. Also comparison between the adaptive frequency tracking method and static impedance matching circuit is made by analyzing simulation results.Comment: 10pages, 10 figures, 3 table