Review and New Developments of Adaptive Tunning Technologies for Wireless Power Transfer

High-power-factor resonant system is of key importance to improve the transmission efficiency and power of inductive-coupled wireless power transfer system. However, quality factor of resonant circuit is vulnerable to system parameter changes, which causes system detuning. The adaptive-tunning technology solve the detuning problem by rematching the resonance parameters so that the system can always work in the resonant state, ensuring the efficient and high-power transmission of the system. Because of the unique features of wireless power transfer system including isolated transmitter and receiver side, delay of communication, and wide-range parameter variation, there is additional challenges of adaptive-tunning technology compared to its application in traditional converters. This paper firstly introduces the resonance characteristic of wireless power transfer system, then summaries the existing adaptive tunning technologies, including frequency tracking and dynamic compensation. Finally, a summary regarding adaptive tunning of WPT systems are discussed.