Figures (13)  Tables (2)

    • Figure 1. 

      (a) Structure of the linked magnetic-concentrating umbrella-shaped transmitting coil. (b) Schematic diagram of magnetic field enhancement in LMU structure.

    • Figure 2. 

      High distance-to-radius ratio WPT system.

    • Figure 3. 

      Equivalent circuit model of high distance-to-radius ratio WPT system.

    • Figure 4. 

      Relationship between transmitting coil radius and power transfer efficiency at different transmission distance.

    • Figure 5. 

      Schematic diagrams of coil structure designs. (a) Hybrid winding array coil. (b) Single-layer LMU transmitting coil. (c) LMU transmitting coil with four-coil configuration. (d) Dual-layer LMU transmitting coil.

    • Figure 6. 

      Relationship between the distance-to-radius ratio of different transmitting coils and transfer efficiency.

    • Figure 7. 

      (a) Magnetic field simulation diagram of hybrid winding array coil. (b) Magnetic field simulation diagram of single-layer LMU transmitting coil. (c) Magnetic field simulation diagram of LMU transmitting coil with four-coil configuration. (d) Magnetic field simulation diagram of Dual-layer LMU transmitting coil.

    • Figure 8. 

      Relationship between the distance-to-radius ratio of different taper angles and power transfer efficiency.

    • Figure 9. 

      Relationship between the distance-to-radius ratio and power transfer efficiency with different number of edge coils.

    • Figure 10. 

      High distance-to-radius ratio WPT experiment system.

    • Figure 11. 

      Comparison of simulation and experimental results of transfer efficiency variation with distance-to-radius ratio at different taper angles of edge coils.

    • Figure 12. 

      Comparison of simulation and experimental results of transfer efficiency variation with distance-to-radius ratio at different sizes of receiving coil.

    • Figure 13. 

      (a) Voltage and current waveform at the transmitting end. (b) Voltage and current waveform at the receiving end.

    • Parameter Symbol Value
      Number of turns of transmitting coil N1 10
      Number of turns of receiving coil N2 10
      Radius of transmitting sub-coil r1 30 mm
      Radius of receiving coil r2 10 mm
      Wire diameter of transmitting coil a1 0.4 mm
      Wire diameter of receiving coil a2 0.2 mm
      Turns spacing of the transmitting coil g1 2.1 mm
      Turns spacing of the receiving coil g2 0.7 mm
      Number of edge coils N 6
      Frequency F 6.78 MHz
      Load resistance R 50 Ω

      Table 1. 

      Parameters of high distance-to-radius ratio WPT system.

    • SISO Ref. [10] Ref. [15] This work
      Area ratio of transmitting and receiving coils 1:1 76:1 1:1 14:1
      Distance-to-radius ratio 8:1 10:1 3:1 8:1
      Transfer power 5 W 20 W 5 W 20 W
      Transfer efficiency 2% 20% 11% 22.36%

      Table 2. 

      Comparison between this study and previous research.