Electrical Power Transfer with “No Wires” - Energy Harvesting Autonomous Sensor Systems - page 207

Signal Generator

FIGURE 6.23
Experimental setup of the WPT system.

P in at the source coil, output power P out at the load coil, and efficiency WPT

of the WPT system, are recorded in Table 6.2 .
Referring to Table 6.2 , it can be observed that the output power and effi-
ciency of the WPT system for different loading conditions (i.e., 2.4 to 12-V
lightbulbs) ranged between 0.6 and1Wand 35% to 50%, respectively. One
interesting observation to note from Table 6.2 is that for the 2.4-V lightbulb,
as the distance between the coils was reduced from 20 to 15 cm, the WPT
efficiency increased by more than a third to around 47.5%. This positive ob-
servation is in line with the conclusion from the discussion of simulation
in Section 6.2.2. Once the one-to-one WPT system was investigated, the fol-
lowing experiment shown in Figure 6.25 was designed to demonstrate the
concept of powering multiple devices, that is, LED load 1 and lightbulb load
2ofdifferent geometries operating at the same resonant frequency.
With reference to Figure 6.25 , it can be seen that a single source and trans-
mitting coil were able to power up two separate load and receiving coils 1