Composite Control to Suppress Output Fluctuation for Receiver Side of Dynamic Wireless Power Transfer System

Mobile device charging is made possible by the dynamic wireless power transfer technology and it is developing toward higher power levels. The output power fluctuates significantly with the movement of the device due to the discontinuous coil switching and the peculiarities of the dynamic magnetic coupler, which has an impact on charging effectiveness and battery life. In this article, a three-level Buck (Buck TL) is used as a dc–dc converter at the receiver side and a composite control aiming to suppress output power fluctuations is proposed. The minimum effective suppression range for the frequency of the coupling fluctuation and the control performance in the transient state are analyzed theoretically. Compared with PI control, the simulation is built, and the 2.6 kW experiment results showed that the composite control could reduce the system output voltage ripple from 13% to 4.4% with resistive load and the output charging current ripple from 22% to 9% with battery load without impacting the efficiency of the Buck TL system, which verified the effectiveness of the proposed composite control strategy.