Improvement in Efficiency of Wireless Power Transfer of Magnetic Resonant Coupling Using Magnetoplated Wire

Abstract

Wireless power transfer is expected in the use of an electric vehicle and a chip card. However, it requires a high efficiency and takes a long distance. In this paper, we propose the use of a magnetoplated wire (MPW), which is a copper wire (COW) whose circumference is plated with a magnetic thin film, to improve transmission efficiency. The MPW can reduce resistances due to the proximity effect comparison with the COW. The inner diameter of COW and MPW coils is d i = 37 mm and their number of turns is n = 10. As a result, the resistances of the COW and MPW at the frequency f = 12 MHz are 6.8  and 4.1 , respectively, which show a reduction of 40%. The quality factors of the COW and MPW at the frequency f = 12 MHz are 83 and 138, respectively, which show an increase of 66%. The efficiencies of the COW and MPW at a transmission distance of 10 mm are 69.8% and 77.7%, respectively, which show an increase of 7.9%.Index Terms-wireless power transfer, magnetic resonant coupling, efficiency, magnetoplated wire, litz wire, quality factor.

A Critical Review of Wireless Power Transfer via Strongly Coupled Magnetic Resonances

“…Then he constructed a 2 kW-700 mm-diameter pad which has horizontal radial tolerance of 130 mm with a 200 mm air gap. Mizuno et al [67] proposed the use of magnetoplated wires to improve the transfer efficiency. Magnetoplated wires are actually a copper wire whose circumference is plated with a magnetic thin film, thus the resistance caused by the proximity effect will decrease.…”

“…On the other hand, quality factors could be enhanced by decreasing the resistance of the coil. Although the adoptive methods are different, the ultimate goals of new spatial layout structure [64], magnetoplated wires [67] and high-temperature superconducting (HTS) transmitter antenna [65] are actually the same, which are to decrease the equivalent resistances of the coils and improve the system transfer efficiency.…”

“…Transient analysis based on CT is sometimes more accurate than that based on CMT [18], thus CT is widely adopted. Various hot research spots, including system architectures [14][15][16][17], frequency splitting [11,24,26,28,48,49], impedance matching methods [20,26,27,[50][51][52][53][54][55][56][57][58][59][60], optimization designs [25,42,[61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77] and practical applications [37,[78][79][80][81]…”

A Review of Contactless Electrical Power Transfer: Applications, Challenges and Future Trends

“…The mixed-resonant coupling model is proposed for a wireless power transfer system improving the efficiency for long distances [89]. It is demonstrated that using a magneto-plated wire instead of copper wire at frequency of 12 MHz reduces skin effect as well as AC resistance and increases the efficiency up to 7.9% in a wireless power transfer system with transfer distance of 10 mm [90]. Overall efficiency and coupling coefficients of different compensated structures are modeled and analyzed for a long primary track in maglev applications [91].…”

Loss Reduction of Transformer for LLC Resonant Converter Using a Magnetoplated Wire

“…MPW is composed of a magnetic thin film that is plated onto the circumference of a copper wire (COW). The MPW decreases the AC resistance because of the proximity effect; an alternating magnetic flux flows through the magnetic thin film with greater permeability and resistivity compared to copper (15)- (17) . In the present study, the transformer resistances using a Litz wire with a copper wire (LCW) and Litz wire with an MPW (LMW) are measured.…”