Background: Detuning is the main problem that affects the efficiency and transmission
distance of the resonant coupling Wireless Power Transmission (WPT). The distance of load and the
offset of the load position could cause serious detuning.
Methods: This paper presents an adjustable coil in which inductance can be adjusted. Then a model
of WPT was established that could compensate resonant frequency automatically using the adjustable
coil. Next, the relationship between the primary resonant frequency and the transmission efficiency
is analyzed from the circuit. The analysis proved that the design of the adjustable coil could
improve the transmission efficiency of the WPT system. Finally, a prototype of WPT system was
Results: The experimental results showed that WPT system with adjustable coil can improve the
transmission efficiency which proves the theoretical research. At the same time, it has essential reference
value for the future research of WPT.
Conclusion: In this paper, aiming at the system detuning caused by some other factors, such as the
position shift of the load during the wireless power transmission, an adjustable coil is proposed.