Efficiency Improvement of Magnetic Coupler with Nanocrystalline Alloy Film for UAV Wireless Charging System with a Carbon Fiber Fuselage

Abstract

Existing research on the magnetic coupler of unmanned aerial vehicle (UAV) wireless charging systems usually ignores the UAV fuselage, but the fuselage causes eddy current loss and reduces a system’s efficiency. Therefore, aiming at the above problems, this paper proposes a design for a magnetic coupler using nanocrystalline cores to reduce the loss caused by the UAV fuselage. First, the parameters of the asymmetric circular coils were designed for higher mutual inductance. The losses caused by the windings and cores were also calculated. Second, for the loss effect of the carbon fiber fuselage, the fuselage was modeled as an additional coil coupled with both the transmitting and receiving coils. The fact that the eddy current induced by the fuselage leads to efficiency reduction is revealed, which has been generally ignored by previous research. Then, the effect of the nanocrystalline alloy was analyzed based on the magnetic circuit model. An optimized nanocrystalline alloy film was applied to reduce eddy current loss and improve coupler efficiency. Finally, an experimental prototype with a 500 W output, 90.3% efficiency, and a 300 mm air gap were fabricated. When compared to the design without UAV material considerations, the coupler efficiency was improved by 7.9%.

A Calculation Method for the Maximum Transmission Power in ICPT Systems Under Non-Sinusoidal Excitation

“…The design of the magnetic coupler in the ICPT system holds paramount importance as it profoundly affects the power transfer capability of the entire system, showcasing the attributes of weakly correlated coupling [9]. This loosely coupled nature implies that the load can only attain maximum power-specifically, the maximum power of the loosely coupled system-when the load impedance aligns with the leakage reactance [10].…”

Design and Optimization of Planar Spiral Coils for Powering Implantable Neural Recording Microsystem

“…It has been found that an optimal load impedance exists that maximizes the system transfer efficiency, and an actual load can be transformed into this optimal load via impedance transformation [ 17 , 18 , 19 ]. In addition to coil optimization, there are some other techniques, such as adding a nanocrystalline core to reduce eddy current loss [ 20 ], using switch-controlled capacitors to realize variable capacitance for self-tuning [ 21 ] and utilizing joint control with variable zero-voltage switching angle for dynamic optimization [ 22 ]. However, those techniques are not preferred for neural recording applications as they may lead to potential biocompatibility or excessive volume issues, especially given the harsh height constraints.…”

DDD coil design for wireless charging of unmanned aerial vehicles

“…13 A magnetic coupler with a nanocrystalline alloy film was created to reduce eddy current loss in the UAV body. 14 The multichannel wireless charger of UAV was developed with compact receivers placed on each leg and multiple wireless transmitters. 15 A coil design using a ferrite core only in the transmitter was developed to reduce UAV's weight and magnetic scattering.…”

“…A small receiving coil and a large transmitting coil were constructed to reduce the weight of UAVs 13 . A magnetic coupler with a nanocrystalline alloy film was created to reduce eddy current loss in the UAV body 14 . The multichannel wireless charger of UAV was developed with compact receivers placed on each leg and multiple wireless transmitters 15 .…”