Effects of Magnetorheological Fluid Cores on Wireless Power Transfer: A Comparative Study

Wireless power transfer (WPT) is a newly developing technology of transferring power without contact and has a wide variety of applications, such as for biomedical implants and for charging electric vehicles (EVs). In this research, the authors developed and experimented with a wide variety of configurations of WPT with different core materials, including magnetorheological (MR) fluids with different concentrations. Configurations with different types of core materials were tested as a function of distance between the coils ranging from 5 to 35 cm to examine a wide range of potential vehicle heights and with misalignments. Mutual inductance was measured for misalignments of up to 24 cm (complete misalignment), whereas voltage and current were measured for misalignments of up to 18 cm, corresponding to 75% of the coil diameter. Results with MR fluids were promising, demonstrating a novel approach to sustain receiver voltage delivery for biomedical and EV charging applications. However, the existence of high transmitter current under misalignment indicates efficiency and power factor trade-offs that must be characterized in future research.