Magnetic Resonance Wireless Power Transfer System Research Articles

Performance of Data Transmission in Wireless Power Transfer with Coil Displacements

SUMMARY This letter investigates the relationship between antenna position and data communication performance in a magnetic resonance wireless power transfer (MRWPT) system. In MRWPT information such as the types of equipments, the required amount of electrical power, or the timing of power transfer should be exchanged. It is assumed here that power transfer coils in the MRWPT system are employed as antennas for data communication. The frequency characteristics of the antennas change due to coil displacements. The power transfer coils are modeled as a band pass filter (BPF) and the frequency characteristics of the filter are presented in this letter. The characteristics of the filter are derived through circuit simulation and resulting data communication performance is evaluated. Numerical results obtained through computer simulation show that the bit error late (BER) performance can be improved by controlling the

A Fast Algorithm for Frequency-Domain Solutions of Electromagnetic Field Computation of Electric Devices Using Time-Domain Finite-Element Method

A fast algorithm for finding the frequency-domain solutions of electromagnetic field computation using time-domain finite-element method (FEM) is presented. Base solutions, which are time-domain solutions when the excitations are substituted by step functions, are computed first using time-stepping FEM in time domain. Then, based on these base solutions in time domain, all solutions in frequency domain at different operating frequencies can be easily and quickly obtained by simple addition and subtraction operations. It can be seen, from a numerical experiment on the performance analysis of a magnetic-resonant wireless power transfer system, that the computing time of the proposed time-domain method is less than 5% of that required if conventional frequency-domain method is used. The proposed method can be generalized and extended to any linear systems.

A Novel Impedance Matching Topology for Magnetically Coupled Wireless Power Transfer

A modified 4-coil magnetic resonance wireless power transfer (MRWPT) system is proposed. Four coils based on 2-coil system with additional two matching coils were used in this topology. When Tx-Rx distance is changed, the input impedance is changed. However, it can be adjusted by coil parameters of matching coils to maintain impedance matching for maximum efficiency. The equivalent circuit of MRWPT system was analyzed for both transmission function and optimum coupling coefficient of the matching coils. By using four spiral resonant coils, these design considerations was experimentally verified. The measured data agreed well with the calculated data and the transmission function of the proposed system was more efficient than that of conventional 2-coil system.

A Design Method of Magnetically Resonanting Wireless Power Delivery Systems for Bio-Implantable Devices

Magnetic resonant wireless power transfer (MRWPT) technology has great potential in delivering power to bio-implantable devices as it obviates the need to have expensive battery replacement surgery. However, no systematic design method has been reported in this important area. In this paper, a design method of MRWPT system for bio-implantable devices, including detailed procedures, is proposed to realize maximum power transfer efficiency. Considerations on the basic dimensions of the system are outlined, and ways to express the impedance coefficients matrix of equivalent circuit model as functions of system variables are given. Experiment is carried out to verify the validity and effectiveness of the proposed design method.