A 3D Wireless Charging Cylinder With Stable Rotating Magnetic Field for Multi-Load Application

Abstract

This paper proposes a 3D wireless charging cylinder with improved compensation topology to generate a stable rotating magnetic field for charging multiple loads around it. The induced voltage of each receiver is kept constant against load variations when the distance between the transmitter and the receiver is fixed. The 3D charging cylinder has a simple configuration with two perpendicular LCL-compensated transmitter coils driven by separate power inverters sharing a common dc source. The system is fully analyzed with the maximum load limit determined, and design guidance is provided. Both theoretical and experimental results demonstrate that the transmitter currents remain constant against load variations when the total load is within the maximum load limit, and the transfer efficiency is increased with the increase of the total reflected impedance. Compared to the conventional series-series (SS) compensated WPT system, the proposed 3D configuration can maintain the transmitter currents to be constant within the maximum load limit so that multiple loads can be added without affecting each other. It has found that the transmitter currents of the proposed configuration are kept constant at their initial values when four loads with the resistance of 0.5 each are randomly placed at 21 cm from the center of the charging cylinder. By contrast, the transmitter currents of the SS compensated WPT system are obviously changed together with the load voltages. INDEX TERMS 3D wireless charging cylinder, constant induced voltage, maximum load limit, multi-load application, stable rotating magnetic field.

Design of a Cylindrical Winding Structure for Wireless Power Transfer Used in Rotatory Applications

“…There are some models that have almost the same level of LMFs as those of the chosen design, such as DL (24,16), as shown in Figure 11 at different rotation angles. Nevertheless, on the basis of efficiency values, DL (30,16) had efficiency of 97.9%, whereas DL (24, 16) had efficiency of 87.1%. Figure 11.…”

“…Figure 6 illustrates the efficiency of each SS-compensated WPT system at a resonant frequency of 950 kHz. On the basis of the value of the coupling coefficient (shown in Figure 5) and the efficiency values in Figure 6, the chosen design was DL (30,16). Figure 6b displays the DL efficiency (30,16).…”

“…On the basis of the value of the coupling coefficient (shown in Figure 5) and the efficiency values in Figure 6, the chosen design was DL (30,16). Figure 6b displays the DL efficiency (30,16). DL (30,16) self-inductances were L Tx1 = 120.68 µH and L Rx1 = 52.068 µH.…”

“…(a) Different models of WPT system with different numbers of turns. (b) Efficiency of chosen design DL (30,16). DL (30,16) self-inductances were LTx1 = 120.68 µH and LRx1 = 52.068 µH.…”

“…(b) Efficiency of chosen design DL (30,16). DL (30,16) self-inductances were LTx1 = 120.68 µH and LRx1 = 52.068 µH. Figure 7 presents the relation between frequency, load, and efficiency, showing that the system was steady at low and high loads.…”